Secondary Buds Research Articles

Vitis vinifera and Vitis labrusca’da Sekonder Tomurcukların Donma Noktalarının Belirlenmesi

This study was carried out to determine ability of secondary buds to winter freezing in two Vitis species viz. Vitis vinifera L. and Vitis labrusca L. In 2016 and 2017, one genotype of V. vinifera and one genotype of V. labrusca were sampled at 3 different periods during winter dormant period. The one-year-old shoots obtained from vineyards in winter and the secondary buds on 4th, 5th and 6th nodes on shoots has been used for freezing test. For freezing test, DTA (Differantial Thermal Analyses) methods has been used and test was started at +4 oC and temperature has been decreased and terminated at -30 oC. According to test results, the highest and the lowest temperatures to start freezing of secondary buds of the genotype belongs to V. vinifera was -16.48 oC and -19.49 oC, respectively. For V. labrusca genotype, these values were -15.77 oC and -20.99 oC, respectively. The short period of exotherm has been occurred in deep dormancy period for both species. As a result, freezing points of secondary buds varied among species as well years and physiological status of plants. Determining of freezing points of secondary buds in grapes, it is possible to make better prediction of winter injury.

Secondary and tertiary budbreak release is enhanced by extended dormancy chilling in 'Shiraz' grapevines

Limited information exists regarding the dormancy of secondary and tertiary buds within the compound bud of grapevines. We were interested to evaluate how extended chilling duration would affect the budbreak percentage of all three bud orders within the compound bud. Dormant potted 'Shiraz' grapevines, with thirty retained buds per vine, were placed in a cool room at 4 °C over a 20-month period to extend dormancy. Vines were then systematically removed over five dates and placed in a controlled growth environment to assess budbreak percentages and cane tissue concentrations of abscisic acid and cytokinins. Budbreak was hastened by at least 13 d with vines receiving any extra chilling compared to no initial chilling. Furthermore, the firstly observed correlative inhibition of basal buds was apparently removed with chilling. Removal of correlative inhibition within the compound bud with increased chilling duration was also observed with the increases of secondary (doubles) and tertiary (triples) buds breaking simultaneously with the primary bud at each node. This resulted in 91 % of the nodes having two developing shoots and 56 % of the nodes presenting three developing shoots by the end of the experiment. Furthermore, a sigmoidal relationship between percent secondary buds and chilling duration was observed. Possible phytohormone connections were observed with the decline of ABA as secondary and tertiary buds broke at 414 d of chilling and depletion of the CKs, which coincided with the greatest rate of primary bud break after 242 d of chilling. Other possible involvement of ABA and Cis-type cytokinin interactions with secondary and tertiary bud dormancy is discussed. The results suggest future investigations into secondary and tertiary bud release within the grapevine using similar techniques may help to better understand the biochemical mechanisms associated with dormancy.

Compensatory Abilities of Canola in Response to Swede Midge (Diptera: Cecidomyiidae) Damage.

Swede midge (Contarinia nasturtii Kieffer) is an invasive, economic pest of canola (Brassica napus L.) that threatens production throughout Canada. Swede midge has up to four overlapping generations, placing canola at risk of multiple infestations in the field. The relationship between single and multiple swede midge infestations at different canola stages, and the resulting impacts on yield, are unknown. Laboratory experiments were conducted to evaluate the impact of single and multiple infestations of swede midge on four plant stages of canola: three-leaf, seven-leaf, primary bud, and secondary bud. Previously, the seven-leaf and primary bud stages were considered vulnerable to swede midge, but we determined that the secondary bud stage is also vulnerable. Evidence of compensation by canola in response to herbivory by swede midge was discovered. Compensation occurred mainly through increased production of tertiary racemes and pods and was maximized with exposure of 4.5-6.5 female midges per plant. Although compensation may increase potential yield, it also results in uneven crop maturation resulting in delayed harvest and yield loss. Consequently, to prevent delays in maturation and harvest, insecticides should be applied before these densities are reached.

Secondary Bud Gas Exchange, Growth, and Fruitfulness of Vitis vinifera L. cultivars, ‘Grenache’ and ‘Cabernet Sauvignon’ Grown on the Texas High Plains

In 2017, the grape and wine industry had an overall economic impact of $13.1 billion within the state of Texas. The majority of grapes grown in Texas are produced within the Texas High Plains American Viticultural Area (AVA). However, vineyards within the Texas High Plains AVA are subject to late spring frosts which can potentially diminish fruit quality, and reduce crop production. To assist in planning and production efforts, Texas High Plains AVA grape growers require information regarding vine secondary bud growth and fruitfulness. Therefore, the objectives of this experiment were to compare the growth and fruitfulness of shoots grown from primary and secondary buds ofVitis viniferaL. ‘Grenache’ and ‘Cabernet Sauvignon’ vines grafted to 110R rootstocks. Vines were planted in an experimental vineyard in 2008. Each year over two consecutive growing seasons (2016 – 2017) vines were exposed to the following treatments: primary bud growth intact, and following bud break allowing primary bud shoot growth to reach 15.0 cm in length then removing primary bud shoots (forcing growth from secondary buds). Gas exchange, growth, fruitfulness, and fruit total soluble solid data were collected each year. Collected data followed similar trends each growing season. Hence, data from each growing season were pooled. Gas exchange data indicate leaves from primary shoots had lower photosynthetic rates, and stomatal conductance when compared to leaves grown on secondary shoots. In addition, ‘Grenache’ leaves had greater gas exchange when compared to ‘Cabernet Sauvignon’ leaves. Pruning weights, vine yield, cluster mass, and total soluble solids were greater for shoots grown from primary buds. ‘Cabernet Sauvignon’ vines had greater pruning weights, but ‘Grenache’ vines had greater crop load (Ravaz Index) and cluster mass. Yield and total soluble solids did not differ between grape cultivars, but the number of clusters from each vine, and berry mass varied with cultivar and bud treatment. In the late spring frost-prone Texas High Plains AVA, cultivar selection continues to be a critical factor for vineyard success. Results indicate decreased yields from all vines with shoot growth only from secondary buds. However, even though ‘Grenache’ and ‘Cabernet Sauvignon’ vines responded differently to bud treatments (‘Cabernet Sauvignon’ vines generally produced a greater number of smaller clusters when compared to ‘Grenache’ vines), for each cultivar overall yield was similar across all bud treatments. Therefore, Texas High Plains AVA and other grape producers now have additional information that may assist them when making critical vineyard management choices.

‘Xiaohe 1’: A New Walnut Cultivar with High Fruit Setting Rate of Secondary Bud Germination after the Harm of Late Frost

‘Xiaohe 1’: A New Walnut Cultivar with High Fruit Setting Rate of Secondary Bud Germination after the Harm of Late Frost

Spring Freeze Damage of Pecan Bloom: A Review

Pecan is native to the United States. The US is the world’s largest pecan producer with an average yearly production of 250 to 300 million pounds; 80 percent of the world’s supply. Georgia, New Mexico, Texas, Arizona, Oklahoma, California, Louisiana, and Florida are the major US pecan producing states. Pecan trees frequently suffer from spring freeze at bud break and bloom as the buds are quite sensitive to freeze damage. This leads to poor flower and nut production. This review focuses on the impact of spring freeze during bud differentiation and flower development. Spring freeze kills the primary terminal buds, the pecan tree has a second chance for growth and flowering through secondary buds. Unfortunately, secondary buds have less bloom potential than primary buds and nut yield is reduced. Spring freeze damage depends on severity of the freeze, bud growth stage, cultivar type and tree age, tree height and tree vigor. This review discusses the impact of temperature on structure and function of male and female reproductive organs. It also summarizes carbohydrate relations as another factor that may play an important role in spring growth and transition of primary and secondary buds to flowers.

The Relationship Between Bud Size and Exotherm Formation in Dormant Buds of Grapevine

This study was conducted to determine the relationship between bud size and low temperature exotherm (LTE) formation in dormant period of grapevines. For this purpose, primary and secondary buds of Karaerik (Vitis vinifera L.) and 53 Pazar 01 (Vitis labrusca) genotypes which are known to have differences between the bud structure and size, were examined separately. In the study carried out in 2016-2017 and 2017-2018 dormant periods, low temperature exotherms were determined by Differential Thermal Analysis (DTA) method in order to determine the freezing point of the buds. Dormant buds of grapevine size were determined by microscopic imaging of the sections taken after histological procedures. It was demonstrated by the DTA test that the buds with different histological structures had different character and number of LTE. In this study, it was determined that bud samples belonging to Vitis vinifera L. form exotherm at lower temperatures than bud samples belonging to Vitis labrusca species. For both genotypes, it was determined by the histological determinations that the primary buds had a larger structure than the secondary buds. In the study, it was found that the buds with an area less than 0.010 mm2 did not produce LTE. As a result of the study, it was found that the bud structure and size were effective on LTE formation of grapevine dormant buds.

BIORREGULADORES PARA LA PRODUCCIÓN DE HIGO BAJO CONDICIONES DE INVERNADERO

La demanda de higo (Ficus carica L.) fresco crece anualmente en el mercado nacional e internacional, y México tiene potencial para convertirse en importante productor mundial. Para lograrlo, es necesario incrementar el rendimiento, adelantar las cosechas y obtener frutos de calidad. La maduración escalonada de los siconos en la planta representa una desventaja económica, por lo que es importante concentrar la producción de higos maduros para reducir la frecuencia de cosechas. Se ha demostrado que los biorreguladores aceleran el desarrollo de los frutos y mejoran su rendimiento y calidad. El objetivo de esta investigación fue analizar el efecto de la aplicación de cinco combinaciones de biorreguladores (thidiazurón, ácido giberélico, ácido glutámico, triptófano y tiamina) sobre la brotación de yemas axilares secundarias, el crecimiento, rendimiento y calidad de frutos de yemas primarias. Como material genético se utilizaron higueras cv. Netzahualcóyotl cultivadas en invernadero. Los tratamientos se aplicaron por aspersión dirigida a las yemas axilares secundarias en reposo. Las variables evaluadas fueron brotación de yemas axilares secundarias, crecimiento y rendimiento del fruto de la yema principal. Al momento de cosecha se evaluó la longitud, diámetro y peso del fruto, color de la epidermis, firmeza, sólidos solubles totales y acidez titulable. Los biorreguladores adelantaron en 15 d el tiempo a la cosecha, excepto la combinación de ácido glutámico y tiamina. En los frutos se incrementó el contenido de sólidos solubles totales (5 a 10 ºBrix), la longitud (≈ 1 cm), el diámetro (≈ 0.5 cm) y el peso individual (5 a 20 g) con respecto al testigo. El color se afectó por los biorreguladores en forma negativa; los higos tuvieron zonas verdes e inmaduras cercanas al pedúnculo. El rendimiento de fruto no presentó diferencias signifiativas. Aunque los tratamientos con biorreguladores mejoraron algunas variables de calidad, ninguna combinación fue consistente para incrementar el rendimiento y la calidad de frutos de higo.

Cold tolerance of some Iranian wild grape (V. vinifera ssp sylvestris) genotypes

All grape cultivars belong to Vinifera species are cold sensitive and (depend on cultivar) can be damaged by the temperature around -15 to -20°C. In this research, the cold tolerance of some Iranian wild grape (Vitis vinifera ssp sylvestris) genotypes was evaluated. After the leaf fall the 4 bud cuttings were prepared from the growing vines in Kahriz Horticultural Research Center in Urmia and then treated with freezing temperatures (-15, -18, -21, -23 and 4°C as a control) in a cold chamber. The percentage of burst buds in greenhouse condition and the percentage of died primary and secondary buds of each genotype in chilling temperature were measured. Electrical conductivity (EC) of buds and cane tissue was also measured. With decreasing temperature, the rate of primary and secondary bud injury increased and there was a significant difference in cold tolerance among tested genotypes. Approximately all Iranian wild grape genotypes were sensitive to cold stress above -15°C but among them, there were moderate cold tolerant genotypes too. H6 and H4 interspecies hybrids with Labrusca species showed higher cold tolerance compared to wild grape genotypes. These results will be valuable for selection of cold tolerance germplasm to use for cold tolerance breeding.

Effect of pruning strategy on 'Syrah' bud necrosis and fruitfulness in Brazilian subtropical Southeast

The change of wine grape harvest from wet season (summer) to dry season (winter) by changing the pruning management has improved quality of wines produced in the Brazilian Southeast. However, the vines need to be spur pruned twice a year, i.e. with a 1st pruning in August (winter pruning) for a vegetative cycle during the hot and wet summer, and a 2nd pruning in January (summer pruning) for a productive cycle during the cold and dry season. This double pruning strategy is made necessary by the fact that latent buds developed during the dry season cycle are not fruitful to support a productive cycle in the following year. This histological study, performed in the South of Minas Gerais State (Brazil), showed that annual single pruning done in the wet season (in January) displayed a high rate of necrosis on primary and secondary buds (bud necrosis – BN). In April, 99 days after summer pruning (DASP), the rates of BN were 40 % and 50 % at basal and apical node positions, respectively, reaching 80 % of BN in December (322 DASP). As a consequence of BN, bud potential fertility was drastically reduced from 0.5 inflorescence primordial (IP) per bud (in July) to 0.06 (in December) and bud burst in the next cycle from secondary and tertiary bud axes. Vines managed by double pruning system (submitted to summer and winter pruning) displayed a much higher fruitfulness potential, i.e. 1.46 IP per bud in December (112 days after winter pruning) and limited BN occurrence (20 %). On single pruned vines, we also observed a significant decrease of starch content in canes, trunks and roots. Internal bud anatomy showed that a random cell breakdown started 70 days DASP. At 211 DASP, all buds showed a large starch granule concentration, raphides and crystals of calcium oxalate inside idioblasts of leaf primordia and also in cortical parenchyma of the vegetative axis. The bud starch content was increased and a positive correlation between necrosis and starch accumulation was observed. The impact of carbohydrate availability on bud necrosis development was discussed. This study showed that the necrosis development towards secondary and tertiary axis of the dry season buds is the main reason of unfruitfulness in the vineyards managed by single pruning in the wet season, making the double pruning compulsory.

Karaerik Üzüm Çeşidinin Kış Gözlerindeki Soğuk Zararının Tarla ve Laboratuvar Koşullarında Belirlenmesi

This study was conducted to detect cold damage in dormant buds of grapevine under field (by shooting test) and laboratory (by sectioning method) conditions. In the determination of the low temperature damage, it has been investigated whether there is a difference between the method of sectioning in laboratory conditions and the real shooting level in the field conditions . The study was carried out in the vineyard which was established with the Karaerik ( V. vinifera L. ) grape cultivar in the Uzümlü district of Erzincan in 2012, 2013 and 2014. Samples of an old grapevine cuttings from the vineyard was transported to the laboratory on the same day and sections were taken in order to determine the damage level. Cold damage was assessed based on 1-4 bud averages. In addition, cold damage was evaluated separately in 1st, 2nd, 3rd and 4th nodes. The mortality rates of primary and secondary buds for the first 1-4 buds average were determined and the vitality rates of tertiary buds were determined in order to determine the ultimate vitality. At the second stage of study, the mortality rates (%) of primary and secondary buds and the viability rates (%) of tertiary buds were determined by counting in spring the shoots come from the primary, secondary, and tertiary buds of the first 4 buds that were left in pruning in vineyard. Secondary and tertiary buds were also considered alive if the primary buds have sprouted in vineyard. In the study that determined the level of damage of the buds, it was found that the difference between the sectioning method and the shooting test was 7.9% in primary buds, 14.56% in secondary buds, and 0.1% in tertiary buds . The mortality rates of primary buds and the viability rates of tertiary buds were found statistically insignificant differences between the methods, but the mortality rates of the secondary buds were found statistically significant differences between the methods.

Developmental transcriptome analysis of floral transition in Rosa odorata var. gigantea.

Expression analyses revealed that floral transition of Rosa odorata var. gigantea is mainly regulated by VRN1, COLs, DELLA and KSN, with contributions by the effects of phytohormone and starch metabolism. Seasonal plants utilize changing environmental and developmental cues to control the transition from vegetative growth to flowering at the correct time of year. This study investigated global gene expression profiles at different developmental stages of Rosa odorata var. gigantea by RNA-sequencing, combined with phenotypic characterization and physiological changes. Gene ontology enrichment analysis of the differentially expressed genes (DEGs) between four different developmental stages (vegetative meristem, pre-floral meristem, floral meristem and secondary axillary buds) indicated that DNA methylation and the light reaction played a large role in inducing the rose floral transition. The expression of SUF and FLC, which are known to play a role in delaying flowering until vernalization, was down-regulated from the vegetative to the pre-floral meristem stage. In contrast, the expression of VRN1, which promotes flowering by repressing FLC expression, increased. The expression of DELLA proteins, which function as central nodes in hormone signaling pathways, and probably involve interactions between GA, auxin, and ABA to promote the floral transition, was well correlated with the expression of floral integrators, such as AGL24, COL4. We also identified DEGs associated with starch metabolism correlated with SOC1, AGL15, SPL3, AGL24, respectively. Taken together, our results suggest that vernalization and photoperiod are prominent cues to induce the rose floral transition, and that DELLA proteins also act as key regulators. The results summarized in the study on the floral transition of the seasonal rose lay a foundation for further functional demonstration, and have profound economic and ornamental values.

In Vitro Proliferation of Female Buds for Induction of Somatic Embryogenesis from False Horn Plantain (AAB, cv. Curraré).

Most cultivated bananas (Musa spp.) are polyploids, and their fruits are seedless and propagated exclusively vegetatively; however, they can also be cloned by micropropagation techniques, viz., direct organogenesis (DO) or somatic embryogenesis (SE). Banana indirect SE (ISE), with an embryogenic callus phase, is possible using young male or female flowers as direct explant depending on the genotype or shoot tips (scalps). For the False Horn Plantain, cv. Curraré (AAB, plantain subgroup), which has a degenerating male bud, female flowers are used to regenerate plants through ISE. Here, a protocol for increasing the number of initial explant material from a single mother plant and its embryogenic response is described. For those purposes, hands with young female buds are in vitro proliferated in the presence of 1 μM indole-3-acetic acid and 2.5 μM thidiazuron. Friable embryogenic cultures, here called ISE-2, obtained from the new proliferative secondary female bud clusters are initiated on medium containing auxins. Embryogenic suspensions are then established from the ISE-2 cultures. Regeneration of plants is achieved from embryogenic suspensions after plating on semisolid medium free of plant growth regulators; greenhouse acclimatized plantlets are ready for banana farming. This study demonstrates that proliferative female buds are a proper choice for ISE.

Effects of water stress on phenolic content and antioxidant activity of African nightshades

Okello OP, Gweyi JPO, Nawiri Mp, Musila W. 2017. Effects of water stress on phenolic contents and antioxidant activity of African nightshades. Biofarmasi J Nat Prod Biochem 15: 79-95. This study aimed at mapping out the distribution of different African Nightshade species in Siaya and Kisii Counties of Kenya and to determine water stress effect on total antioxidant capacity and total phenolic content of two selected African nightshade namely, giant nightshade (Solanum scabrum) and black nightshade (Solanum villosum). Before selection of the two varieties, the study involved farmer field visits, mapping of nightshades present and administration of semi-structured questionnaires to farmers to determine the indigenous vegetables being grown, the nightshade species grown and factors affecting their production. The experiments were conducted both in the field and greenhouse conditions. Watering intervals were at 15 cbars, 50 cbars, and 85 cbars. Data on the number of secondary buds, leaf area, shoot height, shoot and root dry weights were gathered. The total antioxidant capacity and the total phenolic content were recorded using DPPH radical scavenging method and Folin-Ciolcalteu method, respectively. The data collected were subjected to ANOVA. In both counties where production was 100% under small scale, Solanum scabrum was the main variety grown is Siaya County (36%) while in Kisii the main variety was Solanum villosum (32%). There were significant differences (P≤0.05) among treatments in leaf area, plant height, shoot biomass, number of secondary buds, leaf and root total phenolic content and leaf and root antioxidant activity. At all stress levels, Solanum scabrum exhibited the tallest plants with a maximum height of 45.17cm at 15cbars, while Solanum villosum had the shortest plants at all stress levels, with the shortest one being recorded at 16.65 cm at 85 cbars. S. scabrum also had the highest root dry weight (7.78g), shoot dry weight (50.78g) and highest leaf area of (304.45cm2). However, Solanum villosum had the highest number of secondary buds at all stress levels with the highest being 24 at 15 cbars. Concerning phytochemicals, Solanum villosum had a higher concentration of both the total phenolics and antioxidant activity in the shoots (46.41g GAE/Kg DM total phenolic content and 52.68% total antioxidant activity). Meanwhile, Solanum scabrum had a higher concentration in the roots (25.06gGAE/Kg DM total phenolic content and 27.18% total antioxidant activity). Water stress cause a decline in all growth parameters but increased phytochemical accumulation in nightshade accessions grown. It is therefore suggested that for better yields, irrigation should be performed at every 15 cbars, however for adequate phytochemical accumulation, the irrigation should be carried out at 50 cbars. Further research to explore and quantify other phytochemical components as affected by different watering regimes need to be undertaken.

In Vitro Regeneration of Shoots From Nodal Explants of Dendrobium Chrysotoxum Lindl

AbstractTransverse sections (2 mm thickness) of stem-nodes from in vitro raised seedlings had morphogenic potential on semisolid and liquid Murashige and Skoog medium supplemented with cytokinins N6-benzyladenine (BA 4.44 μM), furfurylaminopurine (KIN 4.65 μM) and auxin α-naphthalene acetic acid (NAA 5.37 μM) individually and in combinations. The regeneration response was influenced by both the type of growth regulator and physical state of the medium. The explants produced either shoot buds on cytokinincontaining media or protocorm-like bodies (PLBs) on NAA containing media both solid and liquid. More neo-formations were produced on liquid media, especially those containing only NAA. They were formed at nodal and inter-nodal regions. The secondary buds were produced on the surface of primary PLBs. The plantlets were developed on MS medium containing banana homogenate 50 g·dm-3. The current study is the first ever report on successful regeneration of Dendrobium chrysotoxum from stem-node segments.

Studies on the effect of media on sucker production of banana cv. POOVAN

In vivo macropropagation is an alternative simple and cheap technique for banana multiplication. The experiment was conducted in Completely Randomized Design with 13 treatments in three replications. The treatments consisted of three growing media (FYM, Rice hull, Sawdust), two biofertilizers ( Azospirillum and VAM) with sand alone as control. Observations on the production of primary, secondary and tertiary buds was recorded. The results of the study revealed that use of FYM + VAM (T 7 ) as growing media resulted in increasing the primary, secondary and tertiary bud regeneration. The time taken for emergence of primary, secondary and tertiary buds was also earlier in the treatment T 7 (FYM + VAM).

Structural peculiarities of shoots of switch grass (Panicum virgatum L in the context of introduction in the Right-Bank Forest-Steppe and Polissia zones of Ukraine

Purpose. To define morphological peculiarities of the different types of shoots of switch grass (Panicum virgatum L.) in the context of introduction in the Right-Bank Forest-Steppe and Polissia zones of Ukraine.Methods. Morpho-physiological and ontogenetic analysis, morphometric technique, statistical evaluation.Results. It was found that P. virgatum plants were producing the following types of shoots: vegetative-generative short or long rhizomatous ones (they appeared as in the underground part of a maternal shoot in «the area of shortened internodes» and in the base of its aboveground part); vegetative underground and aboveground ones (they are forming both in the axils of scales of the underground part of a maternal shoot and in the axils of cauline leaves); generative aboveground shoots (borne in the axil of cauline leaves). Morphological parameters and features of morphogenesis of reproduction, resting and secondary buds have been described.Conclusions. During flowering phase of maternal shoot, P. virgatum reproduction buds were on the organogenesis phase I–II, their bursting occured after maternal shoot has flowered. The correlation of internodes length, leave blades and sheaths has been established. The maximum values of the above parameters were observed in the middle part of the prefloral zone of the stem. In the context of introduction, panicle earing came in the third decade of July, flowering began in the first decade of August. It was revealed that complete flowers are bloomed faster than the staminate ones.

Impact of spring freeze on yield, vine performance and fruit quality of Vitis interspecific hybrid Marquette

In viticultural regions with spring freeze events, early budburst increases the risk of vine damages compromising industry long-term sustainability. Marquette is a cold hardy hybrid with Vitis riparia in its parentage, a source of cold hardiness and rapid budburst characteristics. In 2012 and 2013, the capacity of Marquette to rebound from significant bud mortality from a series of spring freeze events was quantified and the capacity of recovering the damages the following year, measuring vine yield and the effect on fruit quality. The compound bud on grapevine is actually three buds in one, with primary, secondary, and tertiary all present. Spring freeze events in 2012 killed over 80% of the shoots arising from primary buds (SPB) while secondary buds (SSB) were almost unaffected. By tracking the performance SPB and SSB, we were able to quantify vine response to spring freeze events. A comparative analysis of phenological and fruit quality characteristics of the SPB and SSB clusters showed different development and ripening of those of SBS. However, the differences disappeared at harvest, with no significant impact on yield or only partially on fruit composition. The results suggest that Marquette has the potential to generate significant yield from SSB with desirable fruit quality and could offer a solution to spring freeze losses. In 2013, year characterized by no spring freeze events, vines recovered full productivity, yielding 61% more fruit, due to an increased number of cluster per vine (+60%) with also better fruit quality at harvest.

Functional characterization of a novel Brassica LEAFY homolog from Indian mustard: Expression pattern and gain-of-function studies

LEAFY plays a central role in regulation of flowering time and floral meristem identity in plants. Unfortunately, LFY function remains uncharacterized in agronomicaly important Brassicas. Herein, we illustrate fine-mapping of expression domains of LFY in 15 cultivars of 6 Brassica species and describe gain-of-function phenotypes in Arabidopsis and Brassica. We depict early flowering and altered fatty-acid composition in transgenic seed. The cDNA encoding BjuLFY (417aa) shared only 85% identity with reported homolog of B.juncea implying distinctness. Quantitative RT-PCR based coarse expression mapping of BjuLFY in tissue samples representing 3 time points at specific days after sowing (DAS), pre-flowering (30 DAS), flowering (75 DAS) and post-flowering (110 DAS), depicted an intense pulse of BjuLFY expression restricted to primary floral buds (75 DAS) which subsided in secondary floral buds (110 DAS); expression in root samples was also recorded implying neo-functionalization. Fine-mapping of expression during flowering confirmed tightly regulated LFY expression during early stages of bud development in 15 cultivars of 6 Brassica species implying functional conservation. Ectopic expression of BjuLFY in A. thaliana and B. juncea caused floral meristem defects and precocious flowering. B. juncea transgenics (T1) over-expressing BjuLFY flowered 20days earlier produced normal flowers. GC–MS analysis of mature seed from Brassica transgenics showed an altered fatty-acid profile suggestive of seed maturation occurring at lower temperatures vis-à-vis control. Our findings implicate BjuLFY as a regulator of flowering in B. juncea and suggest its application in developing climate resilient crops.

Effects of GA3 and ABA on the respiratory pathways during the secondary bud burst in black currants

The effects of exogenous gibberellic acid (GA3) and abscisic acid (ABA) on the total respiratory rate, percentages of total respiratory rate contributed by respiratory pathways [Embden-Meyerhof- Parnas Pathway (EMP), Pentose Phosphate Pathway (PPP), and Tricarboxylic Acid Cycle (TCA)], and conversion of starch to soluble sugars in the buds of black currants during secondary bud burst were investigated to determine the relationship between respiratory rates and secondary bud burst. ‘Adelinia’, a black currant cultivar that is prone to secondary bud burst after the first harvest, was used in this study. Mature bushes of Adelinia were sprayed with 30 mg/L GA3 and 50 mg/L ABA to manipulate bud burst. The results showed that exogenous applications of GA3 and ABA had opposite effects on bud respiratory rate. Generally, GA3 treatment increased the total respiratory rate and respiratory rate of the TCA and PPP, and the respiratory rates after GA3 treatment were higher than those of control. While ABA treatment mostly decreased the total respiratory rate and the respiratory rate of TCA and PPP in buds in comparison to control. In terms of the percentage of the three respiratory rates in comparison to the total respiratory rate, GA3 treatment significantly increased the percentage of TCA and PPP respiratory rate in comparison to the control (P < 0.01), whereas ABA decreased the rates. GA3 significantly increased the content of soluble sugars and decreased the starch content, while the starch content in buds after ABA treatment was significantly higher than that of the control. All results showed that PPP is a critical process for the second bud burst in black currants. While the EMP–TCA pathway is still dominant in bud respiration, provides a series of basic materials and energy (ATP). The conversion of starch to soluble sugars is essential for bud burst. Thus, we conclude that an energy shortage is a main contributor in ABA inhibition of the secondary bud burst of black currants.