Increased Plant Vigor Research Articles

Boron Impact on Maize Growth and Yield: A Review

Maize (Zea mays L.) is a vital crop, contributing significantly—at least 30%—to global dietary energy intake and biofuels and ethanol production. This review article delves into the dynamic interplay between boron (B) and maize growth, yield, and agricultural sustainability. Boron, a crucial micronutrient, is pivotal in essential physiological processes such as root development, leaf expansion, and cob formation. These processes are fundamental for ensuring the vigour and productivity of maize crops. Conversely, boron deficiency manifests as thinner leaves with reduced chlorophyll content, compromising plant health, and hindering yield potential. Maintaining adequate boron levels, particularly during reproductive stages, is critical for mitigating the risk of abnormal ears and maximizing the quantity and quality of maize production. Emerging research underscores the significance of foliar boron application at various growth stages of maize, which stimulates growth, facilitates cell wall development, and increases leaf area. This translates to improved light interception and photosynthetic efficiency, ultimately contributing to increased plant vigour and biomass accumulation. Furthermore, exploring innovative approaches for sustainable boron management is crucial. This includes precision fertilization techniques and biofortification strategies to ensure optimal maize production while minimizing environmental impacts. By gaining a deeper understanding of the complex relationship between boron and maize, farmers can develop customized fertilization plans that utilize strategic foliar boron application. This approach unlocks maize's full yield potential and contributes to sustainable agricultural practices, supporting global food security.

Enhancing cotton sustainability: Multi-factorial intercropping, irrigation, and weed effects on productivity, quality and physiology

Drought stress and weed infestation are significant factors that significantly decrease cotton yield. Increasing the variety of plants within a cotton field ecosystem can strengthen its stability and protect it from susceptibility to both biotic and abiotic pressures. In this two-year experiment (2021 and 2022), the effects of intercropping systems (four growth conditions including mono- and inter-cropped cotton varieties Golestan and Hekmat with Nepeta crispa and dragon's head (Lallemantia iberica)), irrigation (three intervals of 3, 6, and 9 days), and weed competition (weed-free and weedy plots) on the agronomic performance, physiological characteristics, and seed quality of cotton in a semi-arid region of Iran were studied. In 2021, the volume of irrigation water applied was 9873, 6100, and 4650 m3 ha−1 for irrigation intervals of 3, 6, and 9 days, respectively. In 2022, the volumes were 9071, 5605, and 4272 m3 ha−1 for the corresponding irrigation intervals. Over two years, Xanthium strumarium, Amaranthus retroflexus, and Portulaca oleracea were the dominant weed species. Weeds had the most significant impact on total dry weight; weed control increased plant vigor and growth, ranging from 1.4 to 2.3 times, while weed impact on cottonseed yield ranged from 18% to 96% reduction. Increasing irrigation intervals resulted in reductions in various parameters, with decreases of 39%–80% in total dry weight, 34%–57% in cottonseed yield, and 48%–72% in lint yield. The harvest indices for seed cotton, cottonseed, and lint ranged from 35.3% to 56.5%, 18.3%–35.0%, and 15.4%–20.5%, respectively. Weeds were responsible for a 17% decrease in the 1000-seed weight. As the irrigation intervals increased from 3 days to 6 days and 9 days, the number of bolls per plant decreased by 19%–85%. Extending the irrigation interval from 3 days to 6 days and 9 days resulted in a substantial decrease in the photosynthetic rate, ranging from 42% to 92%. Mono-cropped Golestan performed well under unstressed conditions such as 3-day interval irrigation and weed-free conditions. On the other hand, intercropped Hekmat demonstrated better resilience to both moisture and weed stresses. The LER (Land equivalent ratio) indices of both intercropping systems were generally favorable, indicating higher productivity compared to sole cropping. The intercropping systems consistently showed the highest LER indices under weedy conditions, highlighting the significance of intercropping as a valuable method in integrated weed management.

Genetic mapping and transcriptome profiling of a chickpea (Cicer arietinum L.) mutant identifies a novel locus (CaEl) regulating organ size and early vigor.

Chickpea is among the top three legumes produced and consumed worldwide. Early plant vigor, characterized by good germination and rapid seedling growth, is an important agronomic trait in many crops including chickpea, and shows a positive correlation with seed size. In this study, we report a gamma-ray-induced chickpea mutant with a larger organ and seed size. The mutant (elm) exhibits increased early vigor and contains higher proline that contributes to a better tolerance under salt stress at germination, seedling, and early vegetative phase. The trait is governed as monogenic recessive, with wild-type allele being incompletely dominant over the mutant. Genetic mapping of this locus (CaEl) identified it as a previously uncharacterized gene (101503252) in chromosome 1 of the chickpea genome. There is a deletion of this gene in the mutant with a complete loss of expression. In silico analysis suggests that the gene is present as a single copy in chickpea and related legumes of the galegoid clade. In the mutant, cell division and expansion are affected. Transcriptome profiling identified differentially regulated transcripts related to cell division, expansion, cell wall organization, and metabolism in the mutant. The mutant can be exploited in chickpea breeding programs for increasing plant vigor and seed size.

Variable Yield Responses among Grafted and Nongrafted Late blight–resistant Tomato (Solanum lycopersicum L.) Hybrids in North Carolina

Host resistance is an environmentally and economically sustainable disease management strategy that may be especially beneficial to small-scale and organic growers for whom other management tools such as synthetic pesticides are too costly or not permitted. In western North Carolina, the demand for vine-ripened tomatoes (Solanum lycopersicum L.) from local and organic farms has led to the development of cultivars bred for resistance to geographically relevant diseases, including late blight of tomato, which causes rapid defoliation and lesions on fruit. Grafting tomato plants has the potential to increase plant vigor and yield; however, this effect is known to be dependent on multiple factors, including scion and geographic location. In this study, we evaluated the yield response of one determinate (‘Mountain Gem’) and four indeterminate (‘Mountain Heritage’, ‘Mountain Girl’, ‘Mountain Rouge’, and ‘NC10291’) late blight–resistant tomato cultivars, grafted on tomato rootstock ‘Maxifort’ or nongrafted, on a commercial farm and at two research facilities in western North Carolina. Yield of marketable fruit from grafted plants was greater than that from nongrafted plants at one location (P = 0.008); however, yield response of each cultivar, grafted or not grafted, differed by location. Yield was consistently greater from ‘Mountain Gem’ plants than other cultivars, and grafted ‘Mountain Gem’ plants had greater yields later in the season at two locations than nongrafted plants. Because of the late planting date intended to expose cultivars to the late blight pathogen, the full yield potential of the indeterminate cultivars was not realized at all locations. Disease severity caused by Verticillium wilt (Verticillium dahliae Kleb., Verticillium albo-atrum Reinke & Berthold) was lowest for cultivar Mountain Heritage at two of three locations. Results from this study emphasize the importance of conducting evaluations of grafted tomato plants at multiple locations, including on farm, to optimize the benefits associated with their use.

Hormonal Interactions Underlying Rootstock-Induced Vigor Control in Horticultural Crops

Grafting has been utilized to develop horticultural crops to increase plant vigor, yield potential, and tolerance to various environmental stresses. Grafting employs selected rootstocks of the same species or near relatives. Moreover, dwarfing is a desirable feature for intensive cultivation and efficient orchard management. However, information on the regulatory mechanisms of rootstock-induced vigor control remains unclear. Numerous studies comprehend the physiological and molecular mechanism of rootstock control scion vigor, which has significantly improved our understanding regarding vigor control processes in apple, litchi, pear, citrus, etc. This review summarizes the current knowledge on the impact of rootstocks on scion vigor and hormonal mechanisms involved in dwarfing, such as auxin (IAA), cytokinins (CK), abscisic acid (ABA), gibberellic acids (GAs), and brassinosteroids (BR). This study will provide fascinating information for future studies on rootstock-induced dwarfing effects and accelerate the breeding of dwarfing rootstocks.

STUDY OF OLIGO CHITOSAN IN EFFORTS TO IMPROVE THE GROWTH QUALITY OF SHALLOT (Allium ascalonicum L.)

This research is intended to answer the obstacles in the cultivation techniques of shallots, especially in overcoming the low quality of growth, which in turn affects the yield and production of onions. In this experiment, spraying three types of frequency and four kinds of oligo-chitosan concentrations was tried throughout the growing onion period. Oligo-chitosan as a supplement, is given to the onion plants periodically, in various concentrations, in three different types of oligo-chitosan spraying, which they are (F1) given to plants aged 15 DAP and 45 DAP; (F2) given to plants aged 15 DAP, 30 DAP, and 45 DAP; and (F3) given to plants aged 15 DAP, 25 DAP, 35 DAP, 45 DAP. The oligo-chitosan concentration consists of four kinds of concentration, consisting of 0 ‰ (K0) as a control, 1 ‰ (K1), 2 ‰ (K2) and 3 ‰ (K3). The experiment was carried out in the field using a polybag, with a completely randomized environmental design with a 95% accuracy level. To determine the effect of treatment on the quality of growth of shallots, diversity analysis was carried out. From preliminary observations, it shows that the onion bulb growing power as a seed is quite good, while the treatment using oligochitosan gives significant results on increasing plant vigor, compared to not using oligochitosan. As for further observations that at plant height, the number of leaves and the number of tillers up to 50 days after planting, although it does not show any real effect of the treatment that was tried, but it can be suspected that the more frequency treatment given oligo-chitosan, more gives a better chance of yield than a few frequencies, while an oligo-chitosan concentration of 1 ‰ is sufficient to improve the quality of plant growth, then it can be expected that F2K1 will give higher tuber yields.Keyword: shallot, oligo-chitosan spraying frequency, oligo-chitosan concentration

Trichoderma Species: Versatile Plant Symbionts.

Because of the need to provide food for the growing population, agricultural activity is faced with the huge challenge of counteracting the negative effects generated by adverse environmental factors and diseases caused by pathogens on crops, while avoiding environmental pollution due to the excessive use of agrochemicals. The exploitation of biological systems that naturally increase plant vigor, preparing them against biotic and abiotic stressors that also promote their growth and productivity represents a useful and viable strategy to help face these challenges. Fungi from the genus Trichoderma have been widely used in agriculture as biocontrol agents because of their mycoparasitic capacity and ability to improve plant health and protection against phytopathogens, which makes it an excellent plant symbiont. The mechanisms employed by Trichoderma include secretion of effector molecules and secondary metabolites that mediate the beneficial interaction of Trichoderma with plants, providing tolerance to biotic and abiotic stresses. Here we discuss the most recent advances in understanding the mechanisms employed by this opportunistic plant symbiont as biocontrol agent and plant growth promoter. In addition, through genome mining we approached a less explored factor that Trichoderma could be using to become successful plant symbionts, the production of phytohormones-auxins, cytokinins, abscisic acid, gibberellins, among others. This approach allowed us to detect sets of genes encoding proteins potentially involved in phytohormone biosynthesis and signaling. We discuss the implications of these findings in the physiology of the fungus and in the establishment of its interaction with plants.

Evaluation of allyl isothiocyanate as a soil fumigant against soil-borne diseases in commercial tomato (Lycopersicon esculentum Mill.) production in China.

Root-knot nematodes (Meloidogyne spp.), soil-borne diseases and weeds seriously reduce the commercial yield of tomatoes grown under protected cultivation in China. Allyl isothiocyanate (AITC), a natural product obtained from damaged Brassica tissues, was evaluated as a potential replacement for the fumigant methyl bromide (MB) for use in the greenhouse production of tomatoes in China. The dose-response assay indicates that AITC has high biological activity against major bacterial and fungal pathogens (EC50 of 0.225-4.199 mg L-1 ). The bioassay results indicate that AITC has good efficacy against root-knot nematodes (LC50 of 18.046 mg kg-1 ), and moderate efficacy against fungal pathogens (LC50 of 27.999-29.497 mg kg-1 ) and weeds (LC50 of 17.300-47.660 mg kg-1 ). The potting test indicates that AITC significantly improved plant vigor. Field trials indicate that AITC showed good efficacy against Meloidogyne spp. and Fusarium spp. (both ∼ 80%) as well as Phytophthora spp. and Pythium spp. (both ∼ 70%), and improved plant vigor and marketable yield. AITC used as a soil fumigant (30-50 g m-2 ) effectively controlled major bacterial and fungal pathogens, root-knot nematode, weeds and increased plant vigor, yield and farmers' income in tomato cultivated under protected agriculture in China. © 2018 Society of Chemical Industry.

The notoriously destructive potato stalk borer (Trichobaris trinotata) has negligible impact on its native host, Solanum carolinense (horsenettle)

While herbivores can have a wide range of impacts on their host plants, instances in which herbivore damage is truly beneficial are rare. Thus, it was surprising that damage by the potato stalk borer (PSB) was associated with increased fitness of its native host plant (horsenettle) in a recent field study, particularly because this insect can have such severe negative effects on potato crops. A controlled experiment with potted horsenettle was conducted to investigate the impact of damage by PSB to see if it has any negative impacts on the plants, or whether horsenettle truly overcompensates for its damage. Damage by PSB had negligible impact on sexual reproduction and potential future vegetative propagation through root production in this experiment. Additionally, PSB damage did not exacerbate the negative fitness impact of heavy leaf damage by the eggplant lace bug. The lack of positive impacts in the potted horsenettle study suggests that selection for decreased resistance to PSB in the field study was due to correlated selection for increased plant vigor, rather than to overcompensation. That is, when given options, PSB females may preferentially oviposit on larger, healthier plants that are likely to be better hosts for their larvae. An important implication of these results is that a wild weed’s high tolerance of a natural herbivore can compound the weed’s potential to serve as a reservoir from which the herbivore can switch to closely related agricultural plants that are not tolerant of its damage.

Proceso de unión del injerto de empalme en jitomate (Solanum lycopersicum L.)


 
 
 La técnica de injerto en jitomate representa una alternativa sustentable para el control de enfermedades, para incrementar el vigor de planta, mejorar la calidad de fruto y rendimiento. Los primeros factores importantes en el proceso de injerto son la compatibilidad anatómica y el tiempo de establecimiento de la continuidad vascular entre los dos tejidos vegetales, este último determina el momento del trasplante. El objetivo del presente estudio fue evaluar el proceso de unión del injerto con el método de empalme en jitomate, mediante cortes anatómicos del punto de unión; así como, determinar el tiempo de desfasamiento en la siembra entre los genotipos ‘Multifort’y ‘El Cid’(portainjerto e injerto, respectivamente) para sincronizar el diámetro de tallo. Se sembraron 100 semillas de ambos genotipos, de esas plántulas se midieron los diámetros de tallo diariamente. Se tomaron muestras de tejido del punto de unión del injerto a los 5, 10 y 15 días después de la injertación (DDI), los cortes anatómicos fueron de 10 μm de espesor obtenidos con un microtomo rotatorio. Los resultados indicaron, que se requiere sembrar el injerto o púa, dos días antes que el portainjerto para homogenizar el diámetro de tallo a 2 mm (ideal para injertar). En las imágenes de los cortes anatómicos se encontró que a los 5 DDI la línea de demarcación comenzó a reabsorberse y al mismo tiempo dio inicio la formación de nuevo tejido de conducción (xilema y floema), la completa conexión vascular se llevó a cabo a los 10 DDI.
 
 

Nitrogen fertilization in the growth phase of 'Chardonnay' and 'Pinot Noir' vines and nitrogen forms in sandy soil of the Pampa Biome

ABSTRACT Information on nitrogen fertilization in growing vines is still a very limited subject, especially for crops on sandy soils in the Pampa Biome in Rio Grande do Sul, where viticulture has expanded considerably in the last decade. This study aimed to assess the impact of N doses on growth of young plants of Chardonnay and Pinot Noir vines and N forms present in sandy soil in the Pampa Biome. The experiment was conducted from October 2011 to December 2012 in a vineyard in Santana do Livramento, in Southern Rio Grande do Sul State, in soil with 82 g kg-1 clay in the 0-20 cm layer. Vines of Chardonnay and Pinot Noir varieties were subjected to applications of 0, 10, 20, 40, 60, and 80 kg N ha-1 year-1. Total N in leaves, SPAD readings, stem diameter, plant height, and dry matter of the pruned material were evaluated in two growth cycles and three times. Soil samples were collected at 0-10 and 10-20 cm depths at four crop growth stages, in which N-NH4 +, N-NO3 -, and total N were analyzed and the mineral N was calculated. The N levels applied to young vines, although they did not provide relevant changes in the N-NH4 +, N-NO3 -, and mineral N contents in the soil, were able to increase the N content in the leaves, increasing plant vigor. because the reason is that there was an increase in stem diameter, plant height, and dry matter of pruned material in most evaluation periods. These parameters suggest better growth patterns and uniformity of young grapevines with possible positive effects in anticipation of production, demonstrating the importance of nitrogen fertilization strategies to the growing vines in the sandy soil conditions of the Pampa Biome.

In situ morphometric survey elucidates the evolutionary systematics of the Eurasian Himantoglossum clade (Orchidaceae: Orchidinae).

Background and AimsThe charismatic Himantoglossum s.l. clade of Eurasian orchids contains an unusually large proportion of taxa that are of controversial circumscriptions and considerable conservation concern. Whereas our previously published study addressed the molecular phylogenetics and phylogeography of every named taxon within the clade, here we use detailed morphometric data obtained from the same populations to compare genotypes with associated phenotypes, in order to better explore taxonomic circumscription and character evolution within the clade.MethodsBetween one and 12 plants found in 25 populations that encompassed the entire distribution of the Himantoglossum s.l. clade were measured in situ for 51 morphological characters. Results for 45 of those characters were subjected to detailed multivariate and univariate analyses.Key ResultsMultivariate analyses readily separate subgenus Barlia and subgenus Comperia from subgenus Himantoglossum, and also the early-divergent H. formosum from the less divergent remainder of subgenus Himantoglossum. The sequence of divergence of these four lineages is confidently resolved. Our experimental approach to morphometric character analysis demonstrates clearly that phenotypic evolution within Himantoglossum is unusually multi-dimensional.ConclusionsDegrees of divergence between taxa shown by morphological analyses approximate those previously shown using molecular analyses. Himantoglossum s.l. is readily divisible into three subgenera. The three sections of subgenus Himantoglossum—hircinum, caprinum and formosum—are arrayed from west to east with only limited geographical overlap. At this taxonomic level, their juxtaposition combines with conflict between contrasting datasets to complicate attempts to distinguish between clinal variation and the discontinuities that by definition separate bona fide species. All taxa achieve allogamy via food deceit and have only weak pollinator specificity. Artificial crossing demonstrates that intrinsic sterility barriers are weak. Although we have found evidence of gene flow among and within the three sections of subgenus Himantoglossum, reports of natural hybrids are surprisingly rare, probably because putative parents are sufficiently similar to questionably warrant the status of species. Phenological separation and increased xeromorphy characterise the origin of subgenus Barlia. Several individual morphological characters show evidence of parallel acquisition, and loss of features is especially frequent in floral markings among members of section caprinum. Detailed patterns of gain and loss demonstrate that several different categories of flower markings are inherited independently. Along with the dimensions of labellar lobes, these pigmentation characters have been over-emphasised in previous taxonomic treatments. Increased plant vigour was a crucial element of the origin of the genus, but vegetative characters underwent remarkably little subsequent evolution. Attempts to reconstruct hypothetical ancestors at internal nodes of the phylogeny are weakened by (a) uncertain placement of Steveniella as sister to Himantoglossum s.l. and (b) uncertain relationships among subtly different putative species within section caprinum. Nonetheless, heterochronic/allometric trends, ultimately limited by functional constraints, clearly dictate transitions between contrasting flower sizes and complex labellum shapes.

Nutrient Assimilation in Southern Highbush Blueberry and Implications for the Field

Successful blueberry (Vaccinium sp.) cultivation typically requires soils with low pH, high organic matter, readily available iron, and nitrogen (N) in the ammonium form. Growth of blueberry on typical mineral soils (higher pH, low organic matter) is reduced. Although soil pH effects on nutrient availability and uptake are known, it is unclear if the requirement for low soil pH in blueberry production is due to effects on nutrient availability/uptake or is a more direct effect of rhizosphere pH on root function. In addition, it is unclear if the requirement for high organic matter (soil amendments) is related directly to nutrient availability/uptake. Several studies have examined the use of rootstocks to increase soil adaptation of blueberry and some of these rootstocks have been found to increase plant vigor and yield. In particular, we have investigated whether sparkleberry (Vaccinium arboreum)—a wild blueberry species that is adapted to high pH and low organic matter soils—could be used as a rootstock for commercial production of blueberry on mineral soils. Our work indicates that both nitrate (NO3−) and iron (Fe) uptake and assimilation are greater in sparkleberry compared with southern highbush blueberry [SHB (Vaccinium corymbosum interspecific hybrid)]. This is correlated with increased activity of nitrate reductase (NR) and iron chelate reductase, the rate limiting enzymes for NO3− and Fe acquisition, respectively. Field studies comparing growth and yield of own-rooted vs. grafted ‘Meadowlark’ and ‘Farthing’ SHB in amended vs. nonamended soils are ongoing. In general, own-rooted plants on amended soils exhibit greater growth than own-rooted on nonamended soils, while grafted plants in either soil system exhibit intermediate growth. Yields generally followed this pattern. Our preliminary results suggest that tolerance of SHB to mineral soils is greater when plants are grafted onto sparkleberry than when grown on their own roots. However, growth and yield of grafted plants grown under mineral soil conditions may not equal or exceed that of own-rooted plants grown under optimum soil conditions, at least in the first years after field planting. Longer term studies are necessary to fully evaluate the potential of using sparkleberry and other blueberry species as rootstocks for SHB and northern highbush blueberry (V. corymbosum).

GREEN MANURES IN 'KENT' MANGO ORCHARD

Continuous and intensive use of the soils of the Lower-Middle Sao Francisco River Valley (Vale do Submedio Sao Francisco) through the growing of mango trees in irrigated systems has caused soil degradation and consequently threatened the quality and sustainability of this agribusiness activity in the region. The predominant soil cover in this region has a sandy texture and low organic matter content and water retention capability, which are further compromised by high temperatures and insolation which cause serious restrictions to agricultural productivity when associated with inadequate irrigation management. The aim of this paper was to study crop systems (green manures) used as cover crops and green manure in the establishment of a ?Kent? mango tree orchard by means of quantification and mineral composition of the plant matter resulting from each one of the formative prunings. The leguminous plants used in the intercropped plant mixture were: Calopogonium mucunoide Desv., Crotalaria juncea L., Crotalaria spectabilis Roth., Canavalia ensiformes DC., Cajanus cajan L., Dolichos lablab L., Mucuna aterrina L., and Mucuna conchinchinensis L. The mixture also included non-leguminous species, such as: Sesamum indium L., Chysantemum peruviamum maius, Ricinus communis L., Penissetum americanum L. and Sorghum vulgare Pers. Three plants per plot in four replications were used for evaluations. The mean value of fresh matter production resulting from each one of the four prunings of establishment of the orchard showed that the intercropped plant species mixture with 75% leguminous plants and 25% non-leguminous plants increased plant vigor. Increases were 16.6, 19.7, 45.1 and 23.9% at pruning 1, 2, 3 and 4, respectively, when compared to the treatment of spontaneous vegetation without soil turnover. Significant differences were observed between the treatments in relation to total content of nitrogen, phosphorus, potassium, calcium, and magnesium in the leaves and accumul ated branches at the end of the formative prunings of the plants. The use of intercropped plant species mixtures allows the orchard establishment period to be shortened, which makes it possible to advance the time for beginning management of flower induction and production of mango trees of the Kent cultivar.

Is the loss of Australian digging mammals contributing to a deterioration in ecosystem function?

Abstract Despite once being described as common, digging mammal species have been lost from the Australian landscape over the last 200 years. Around half of digging mammal species are now extinct or under conservation threat, and the majority of extant species have undergone marked range contractions. Our aim is to identify the role of digging mammals in ecosystem processes throughout Australia. We highlight how the actions of digging mammals are vital for maintaining ecosystem functioning and how their extirpation has led to loss of ecosystem functions. A review of the literature indicates that many aspects of the influence of bioturbation on ecosystem functioning have been studied. The role of digging mammals in arid and semi‐arid zones has been previously established. We collate and review a broader scope of studies, including those carried out in the mesic woodlands and forests of Australia. We identify roles of digging mammals in the context of ecosystem functioning and conservation management. Bioturbation significantly alters soil processes, increasing soil turnover and altering the chemical and structural properties of soil. Greater water infiltration and decreased surface run‐off and erosion alter soil hydrophobicity and increase soil moisture. Diggings capture organic matter, provide habitat for a diversity of microscopic and macroscopic organisms, and increase nutrient cycling. Mycophagous mammals disperse fungi (e.g. mycorrhizae), while all diggings can create suitable sites for fungal growth. Diggings also capture plant seeds, increasing seedling germination, recruitment and plant growth. The overall effect of mammal diggings is therefore increased plant vigour and resilience, increased biodiversity and consequently improved ecosystem functioning. We propose that the loss of digging mammals has contributed to the deterioration of ecosystems in Australia. Recognising the roles of digging mammals will inform potential management options such as species translocations or reintroductions.

Specific changes in total and mitochondrial proteomes are associated with higher levels of heterosis in maize hybrids

The phenomenon of hybrid vigor (heterosis) has long been harnessed by plant breeders to improve world food production. However, the changes that are essential for heterotic responses and the mechanisms responsible for heterosis remain undefined. Large increases in biomass and yield in high-heterosis hybrids suggest that alterations in bioenergetic processes may contribute to heterosis. Progeny from crosses between various inbred lines vary in the extent of vigor observed. Field-grown maize F₁ hybrids that consistently exhibited either low or high heterosis across a variety of environments were examined for changes in proteins that may be correlated with increased plant vigor and yield. Unpollinated ears at the time of flowering (ear shoots) were selected for the studies because they are metabolically active, rich in mitochondria, and the sizes of the ears are diagnostic of yield heterosis. Total protein and mitochondrial proteomes were compared among low- and higher-heterosis hybrids. Two-dimensional difference gel electrophoresis was used to identify allelic and/or isoform differences linked to heterosis. Identification of differentially regulated spots by mass spectrometry revealed proteins involved in stress responses as well as primary carbon and protein metabolism. Many of these proteins were identified in multiple spots, but analysis of their abundances by label-free mass spectrometry suggested that most of the expression differences were due to isoform variation rather than overall protein amount. Thus, our proteomics studies suggest that expression of specific alleles and/or post-translational modification of specific proteins correlate with higher levels of heterosis.

Mobility of Transgenic Nucleic Acids and Proteins within Grafted Rootstocks for Agricultural Improvement.

Grafting has been used in agriculture for over 2000 years. Disease resistance and environmental tolerance are highly beneficial traits that can be provided through use of grafting, although the mechanisms, in particular for resistance, have frequently been unknown. As information emerges that describes plant disease resistance mechanisms, the proteins, and nucleic acids that play a critical role in disease management can be expressed in genetically engineered (GE) plant lines. Utilizing transgrafting, the combination of a GE rootstock with a wild-type (WT) scion, or the reverse, has the potential to provide pest and pathogen resistance, impart biotic and abiotic stress tolerance, or increase plant vigor and productivity. Of central importance to these potential benefits is the question of to what extent nucleic acids and proteins are transmitted across a graft junction and whether the movement of these molecules will affect the efficacy of the transgrafting approach. Using a variety of specific examples, this review will report on the movement of organellar DNA, RNAs, and proteins across graft unions. Attention will be specifically drawn to the use of small RNAs and gene silencing within transgrafted plants, with a particular focus on pathogen resistance. The use of GE rootstocks or scions has the potential to extend the horticultural utility of grafting by combining this ancient technique with the molecular strategies of the modern era.

High Tunnel and Open Field Production of Floricane- and Primocane-fruiting Raspberry Cultivars

Identical trials were conducted in a multibay high tunnel and an adjacent open field in southwestern Michigan to compare primocane-fruiting cultivars (Autumn Britten, Caroline, Chinook, Heritage) and floricane-fruiting cultivars (Canby, Encore, Heritage, Nova) of red raspberry (Rubus idaeus). Floricane-fruiting plots of ‘Heritage’ were pruned to produce fruit on floricanes and primocanes (double cropping). The most productive cultivars in both environments were ‘Nova’ and ‘Canby’ (floricane) and ‘Caroline’ and ‘Heritage’ (primocane). These cultivars produced annual yields of 5.5 kg·m−1 row in the tunnel and 2.5 kg·m−1 row in the field. The order of primocane harvest (earliest to latest) was the same in the tunnel and field: ‘Autumn Britten’, ‘Caroline’, ‘Chinook’, and ‘Heritage’. Cultivars with the greatest average berry weight in the tunnel and field were Encore and Nova (floricane) and Autumn Britten and Caroline (primocane). ‘Chinook’ and ‘Autumn Britten’ tended to have the highest incidence of gray mold (Botrytis cinerea) of primocane-fruiting cultivars, but incidence was similar in floricane cultivars. Overall mold incidence was 1% in the tunnel and 13% in the field. Leaf spot (Sphaerulina rubi), cane anthracnose (Elsinoe veneta), spur blight (Didymella applanata), and botrytis cane blight (B. cinerea) were common in the field but absent in tunnel. Phytonutritional analyses of primocane fruit indicated that genotype differences were not consistent across the two environments. Relative cultivar characteristics (harvest season, yield, berry quality) were similar in the field and tunnels, but the tunnel environment tended to increase plant vigor, yield, and fruit quality and suppress several diseases.

Effects of soil amendment with poultry manure on carnation Fusarium wilt in greenhouses in southwest Spain

In a search for alternatives to methyl bromide for controlling carnation vascular wilt caused by Fusarium oxysporum f. sp. dianthi ( Fod), poultry manure plus soil solarization was studied in soil under greenhouse conditions in four 2-year experiments. These were conducted in naturally infested soil to compare the effects of this treatment with soil solarization alone and methyl bromide. Soil treatments were performed during June 2000 for Experiment 1, from July to mid-August 2002 for Experiment 2, from late July to late August 2006 for Experiment 3 and from late May to late June 2008 for Experiment 4. Additionally, a treatment with commercial poultry manure pellet plus soil solarization was included in the two latter experiments. Poultry manure caused reductions of Fod viability in soil samples at depths of 15 and 30 cm, ranging respectively from 93 to 100% and 89 to 100% for Experiments 1, 2 and 3. Carnations planted in plots treated either with poultry manure, methyl bromide or soil solarization had lower final disease incidences, smaller areas under their disease progress curves and higher yields in comparison with untreated plots in Experiments 2, 3 and 4. In Experiment 1, soil solarization was performed under suboptimal conditions, and it provided disease levels and yields similar to those of the untreated control plots. Nevertheless, under the same conditions, previous amendment of Fod-infested soil with poultry manure increased disease control over soil solarization alone, improved carnation yield and quality and also increased plant vigor, thus providing a satisfactory alternative to methyl bromide. The application of organic amendment to the same plot before every crop cycle is recommended to ensure continuous disease control, but the rates of application could be reduced to half for the third and fourth crop cycles, thereby reducing undesirable environmental effects.

Greater performance of introduced vs. native range populations of Microstegium vimineum across different light environments

Non-native plant invaders may undergo evolutionary changes through founder effects, hybridization, adaptation to novel environments, or other processes. Genetic changes in introduced populations may promote invasiveness by increasing plant vigor and plasticity. To determine if introduced populations of the annual grass Microstegium vimineum exhibit greater growth than populations from the native range, we grew plants from 10 native (China) and 10 introduced (U.S.) populations in the greenhouse under two light environments and evaluated growth and morphological traits across two harvest dates. Microstegium from introduced populations had on average 50% and 35% greater biomass in the shade and sun, respectively, than native populations at the first harvest and 59% and 33% greater biomass by the second harvest date. We found no difference in plasticity for growth across the light treatments between native and introduced populations. There were significant morphological differences in resource allocation with native populations producing greater leaf area and leaf mass per stem mass than introduced populations. However, introduced populations produced more biomass overall, despite lower allocation to leaves, which suggests greater efficiency of photosynthesis or lower respiration. These results demonstrate significant genetic differences between introduced and native populations of Microstegium for growth and morphological characteristics. Evolution of Microstegium and other introduced species may complicate the prediction and management of biological invasions.