Temperate Crops Research Articles

Chilling requirement for seed germination and phenological observations on peach cultivars

In subtropical climate areas, the models and methods proposed to evaluate the chilling requirement of temperate fruit crops often do not provide satisfactory results, thus calling for the development of alternative techniques. The aim of this study was to evaluate the correlations between some phonological traits and chilling requirement for seed germination of 18 peach cultivars and one nectarine cultivar. Two experiments were installed separately for the correlation studies. In experiment 1, the phenological traits were observed in the field, while in experiment 2, the chilling requirement for 50 and 100% seed germination of each cultivar was assessed. The number of days for beginning of bloom (r = 0.70**, 0.61**) and full bloom (r = 0.72**, 0.76**) were both significantly correlated with the number of chilling units for 50% and 100% germination of seeds. The number of days for beginning of budding and dormancy break were both significantly correlated with the number of chilling units for 50% and 100% germination (r = 0.48*, 0.50*, respectively). However, the same significant effect for these phenological traits was not found between chilling units and 50% germination of seeds, as well as between chilling units and harvest dates.

Expression conservation within the circadian clock of a monocot: natural variation at barley Ppd-H1affects circadian expression of flowering time genes, but not clock orthologs

BackgroundThe circadian clock is an endogenous mechanism that coordinates biological processes with daily changes in the environment. In plants, circadian rhythms contribute to both agricultural productivity and evolutionary fitness. In barley, the photoperiod response regulator and flowering-time gene Ppd-H1 is orthologous to the Arabidopsis core-clock gene PRR7. However, relatively little is known about the role of Ppd-H1 and other components of the circadian clock in temperate crop species. In this study, we identified barley clock orthologs and tested the effects of natural genetic variation at Ppd-H1 on diurnal and circadian expression of clock and output genes from the photoperiod-response pathway.ResultsBarley clock orthologs HvCCA1, HvGI, HvPRR1, HvPRR37 (Ppd-H1), HvPRR73, HvPRR59 and HvPRR95 showed a high level of sequence similarity and conservation of diurnal and circadian expression patterns, when compared to Arabidopsis. The natural mutation at Ppd-H1 did not affect diurnal or circadian cycling of barley clock genes. However, the Ppd-H1 mutant was found to be arrhythmic under free-running conditions for the photoperiod-response genes HvCO1, HvCO2, and the MADS-box transcription factor and vernalization responsive gene Vrn-H1.ConclusionWe suggest that the described eudicot clock is largely conserved in the monocot barley. However, genetic differentiation within gene families and differences in the function of Ppd-H1 suggest evolutionary modification in the angiosperm clock. Our data indicates that natural variation at Ppd-H1 does not affect the expression level of clock genes, but controls photoperiodic output genes. Circadian control of Vrn-H1 in barley suggests that this vernalization responsive gene is also controlled by the photoperiod-response pathway. Structural and functional characterization of the barley circadian clock will set the basis for future studies of the adaptive significance of the circadian clock in Triticeae species.

Burkholderia phytofirmansPsJN Acclimates Grapevine to Cold by Modulating Carbohydrate Metabolism

Low temperatures damage many temperate crops, including grapevine, which, when exposed to chilling, can be affected by symptoms ranging from reduced yield up to complete infertility. We have previously demonstrated that Burkholderia phytofirmans PsJN, a plant growth-promoting rhizobacteria (PGPR) that colonizes grapevine, is able to reduce chilling-induced damage. We hypothesized that the induced tolerance may be explained at least partly by the impact of bacteria on grapevine photosynthesis or carbohydrate metabolism during cold acclimation. To investigate this hypothesis, we monitored herein the fluctuations of photosynthesis parameters (net photosynthesis [P(n)], intercellular CO(2) concentration, stomatal conductances, ΦPSII, and total chlorophyll concentration), starch, soluble sugars (glucose, fructose, saccharose, mannose, raffinose, and maltose), and their precursors during 5 days of chilling exposure (4°C) on grapevine plantlets. Bacterization affects photosynthesis in a non-stomatal dependent pattern and reduced long-term impact of chilling on P(n). Furthermore, all studied carbohydrates known to be involved in cold stress tolerance accumulate in non-chilled bacterized plantlets, although some of them remained more concentrated in the latter after chilling exposure. Overall, our results suggest that modification of carbohydrate metabolism in bacterized grapevine plantlets may be one of the major effects by which this PGPR reduces chilling-induced damage.

Gene expression analysis of chilling requirements for flower bud break in peach

With 2 figures and 2 tablesAbstractDormancy has been defined as the inability to initiate growth from meristem under favourable environmental conditions. The length of dormancy is a genotype‐specific trait that limits the climatic adaptability of temperate crops, as peach. A better knowledge of the genes involved in dormancy may provide genetic tools for an early assessment of the trait in breeding programmes. Recent studies on the molecular aspects of dormancy provided an initial description of candidate genes involved in bud dormancy maintenance and release in peach. In this paper, we compare the chilling requirement for dormancy release of five peach cultivars with the expression of five genes and ESTs related to bud dormancy: DAM5, DB396 (ppa007606m), DB247 (ppa012188m), SB280 (ppa006974m) and PpB63 (ppa008309m). Results indicated that gene expression analysis could contribute to estimate the chilling requirement for dormancy release of new cultivars.

Dew, where and when? ‘There are more things in heaven and earth, Horatio, than are dreamt of in your philosophy …’

Dew, where and when? ‘There are more things in heaven and earth, Horatio, than are dreamt of in your philosophy …’

Effects of temperature, illumination and node position on stem propagation of Miscanthus × giganteus

AbstractThe sterile triploid Miscanthus × giganteus is capable of yielding more biomass per unit land area than most other temperate crops. Although the yield potential of M. × giganteus is high, sterility requires all propagation of the plant to be done vegetatively. The traditional rhizome propagation system achieves relatively low multiplication rates, i.e. the number of new plants generated from a single‐parent plant, and requires tillage that leaves soil vulnerable to CO2 and erosion losses. A stem‐based propagation system is used in related crops like sugarcane, and may prove a viable alternative, but the environmental conditions required for shoot initiation from stems of M. × giganteus are unknown. A study was conducted to investigate the effect of temperature, illumination and node position on emergence of M. × giganteus shoots. Stems of M. × giganteus were cut into segments with a single node each, placed in controlled environments under varied soil temperature or light regimes and the number of emerged shoots were evaluated daily for 21 days. At temperatures of 20 and 25 °C, rhizomes produced significantly more shoots than did stem segments (P = 0.0105 and 0.0594, respectively), but the difference was not significant at 30 °C, where 63% of stems produced shoots compared to 80% of rhizomes (P = 0.2037). There was a strong positive effect (P = 0.0086) of soil temperature on emergence in the range of temperatures studied here (15–30 °C). Node positions higher on the stem were less likely to emerge (P < 0.0001) with a significant interaction between illumination and node position. Planting the lowest five nodes from stems of M. × giganteus in 30 °C soil in the light resulted in 75% emergence, which represents a potential multiplication rate 10–12 times greater than that of the current rhizome‐based system.

BERRY TRIALS IN THE AZORES

The Direccao de Servicos de Agricultura e Pecuaria, Ponta Delgada, Sao Miguel, Acores, Portugal, began a collaboration with the United States Department of Agriculture, Agricultural Research Service, National Clonal Germplasm Repository at Corvallis, Oregon, and The Ohio State University, Department of Entomology in 2004. While previous horticultural production in the Azores included bananas, pineapples, apples, pears, and grapes, the cultivated temperate zone berry crops have not been grown extensively. Our objective was to compare berry cultivars in the Azores. Between 2006 and 2009, plantings of southern highbush blueberries, Vaccinium corymbosum, 'Emerald', 'Jewel,' 'Misty' and 'O'Neal'; of northern highbush blueberries, V. corymbosum, 'Brigitta', 'Duke' and 'Elliott'; and a rabbiteye cultivar, V. virgatum, 'Spring High', were established in Furnas and in Ponta Delgada. In 2007 and 2009, plantings of thornless blackberry Rubus hybrid 'Triple Crown', and two cultivars of red raspberries, Rubus idaeus 'Heritage' and 'Taylor', were established. In Furnas, only the 'Emerald' blueberry produced fruit in 2008 and 2009. The average yield in the first year was 0.4 kg/plant; in 2009 it was 2.6 kg/plant. The average fruit diameter was 13.95 mm, and weight was 2.44 g. The other cultivars did not produce fruit and the 'Jewel' plants were susceptible to leaf rust disease caused by Naohidemyces vaccinii (Wint.) Sato, Katsuya et Hiratsuka (=Pucciniastrum vaccinii). The blackberry plants produced fruit in 2009. Bud break occurred very late in the season (beginning of June) and the crop season extended from 26 August to 17 December although during the last month only a few fruit were produced. The production peak occurred on the first week of October. The 'Heritage' red raspberry fruit first ripened on 7 August and finished 14 September. The maximum production occurred on 17 August. The average fruit diameter was 15.93 mm, length was 17.50 mm, and weight was 2.60 g/berry. The raspberries became infested with the insect Spodoptera littoralis (Boisduval). 'Taylor' was more susceptible than 'Heritage' to this lepidopterous pest. Trials are continuing.

Evolution and perspective of the temperate fruit crops in São Paulo state, Brazil

This work was carried out to show the current situation of the temperate fruit crops in São Paulo state, Brazil, with an emphasis on grapes, peaches, apples, plums, nectarines and pears crops. Current economic data of crops, major growing regions, main cultivars produced, as well as the new technologies generated by research are presented. Regarding the grape crop, a decrease in the national production as well as in the major growing states was observed. The main grapes growing centers in São Paulo state are presented, highlighting its peculiarities regarding cultivars, cultural crop management and current researches. A trend has been observed toward increasing Niagara Rosada grape growing area rather than the fine table grape cultivars. It was also observed the adoption of cultural practices, aiming to increase productivity, to improve the fruits quality and to reduce manpower necessity. In terms of stone fruits, peaches are the most widely cultivated in São Paulo state, followed by plums and nectarines. Both for stone fruits crop and for apples and pears crops, statistics and comments are presented on the crops evolution as well as the current researches results and the requirements of these fruit crops in São Paulo state, Brazil.

Toxicological and ultrastructural analysis of the impact of pesticides used in temperate fruit crops on two populations of Chrysoperla externa (Neuroptera, Chrysopidae)

Avaliaram-se os efeitos de (g i.a. L-1) abamectina (0,02), carbaril (1,73), enxofre (4,8) fenitrotiona (0,75), metidationa (0,4) e triclorfom (1,5) sobre a sobrevivencia de larvas e pupas, na oviposicao de adultos e viabilidade de ovos de Chrysoperla externa de duas populacoes (Bento Goncalves e Vacaria, Rio Grande do Sul). Alteracoes morfologicas causadas por abamectina em ovos depositados por C. externa da populacao de Vacaria foram avaliadas por meio de analises ultra-estruturais. Os agrotoxicos foram aplicados sobre placas de vidro. Agua destilada foi utilizada como testemunha. Para avaliacao da mortalidade de larvas utilizou-se delineamento experimental inteiramente ao acaso, em esquema fatorial 2 x 7 (duas populacoes x sete tratamentos) e para avaliacao dos efeitos dos compostos sobre a capacidade de oviposicao e viabilidade de ovos utilizou-se esquema fatorial 2 x 4. Carbaril, fenitrotiona e metidationa causaram 100% de mortalidade das larvas. Abamectina reduziu a viabilidade de ovos de C. externa, provenientes de larvas de terceiro instar de ambas as populacoes; entretanto, apresentou toxicidade mais elevada sobre insetos de Vacaria. Analises ultra-estruturais evidenciaram que abamectina causou deformacoes na micropila e na superficie externa do corion de ovos de C. externa. Baseando-se no efeito total (E), carbaril, fenitrotiona e metidationa sao prejudiciais a C. externa; triclorfom e inocuo, enquanto abamectina e enxofre sao inocuos e levemente prejudiciais a larvas de terceiro instar oriundas de Bento Goncalves e Vacaria, respectivamente.

Strategies for Map-Based Cloning in Apple

The apple, Malus × domestica Borkh, is one of the most important temperate fruit crops grown around the world. Although the apple is a diploid (2n = 34), it originated as an allopolyploid and has a relatively small genome size of 750 Mb/haploid. The apple is self-incompatible, highly heterozygous, and displays a juvenile period of 6 to 10 years or more. These characteristics contribute to long-term and difficult efforts to breed new cultivars of apple. However in the past 15 years, significant advances have been made to develop molecular markers linked to traits of economic interest for apple. In turn, these molecular markers have been used to map, clone, and isolate genes. Efforts to pursue map-based cloning in apple have been quite successful in identifying and characterizing target genes, particularly those controlling disease and pest resistance. Strategies of chromosome walking and chromosome landing have provided viable approaches to locate, isolate, and clone some of these genes. In this review, we provide detailed information for these strategies and their use to clone some of these target genes controlling qualitative traits.

Photosynthesis and growth of newly established shoots of Cirsium arvense and Tussilago farfara are resource independent

Nkurunziza L, Rosenqvist E & Streibig JC (2011). Photosynthesis and growth of newly established shoots of Cirsium arvense and Tussilago farfara are resource independent. Weed Research 51, 33–40. Summary Cirsium arvense and Tussilago farfara are noxious creeping perennial weeds of temperate crops. Cirsium arvense infests both conventional and organic crops, while T. farfara is more common in organic cropping systems. Mechanical control used in organic farming often leaves intact shoots within crop rows. It is unknown whether shoots and rhizomes are affected by cutting adjacent interconnected shoots. In glasshouse experiments, comparison of net photosynthesis, chlorophyll a fluorescence and quantum efficiency (Fv/Fm) of disturbed and undisturbed clones, did not show any disturbance effect. Maximum net photosynthesis decreased over time in both disturbed and undisturbed clones, depending on environmental conditions. Maximum net photosynthesis was not affected by the size of removed shoots and the Fv/Fm did not change much from the theoretical value of 0.83. These results imply that there were no source/sink relations in established shoots acting as feedback control for photosynthesis. The resource sharing via horizontal roots/rhizomes did not exist at the rosette growth stage in homogeneous environments. Therefore, both species do not benefit from their clonal interconnectedness as perennial weeds to cope with disturbances, as compared with annual weeds. Further studies are required to investigate this in heterogeneous environments.

Global Warming Impact: Flood Events, Wet-Dry Conditions and Changing Scene in World Food Security

Agriculture is weather-dependent so a significant alteration in the world climate would cause lot of changes in agricultural practice and agricultural productivity in the world. For man to feed himself adequately man must adjust his food production activities in line with the changes in the weather and climate. This paper elucidates the effects of climate change on regional shifts in world production of grain crops. It looks into the flood events, wet-dry conditions in certain regions in the world and the influence of these events on agricultural productivity and food security. Mitigation efforts to secure food in the world are suggested. North America now has warmer and shorter winter, increased spring run-off, drier summer and a shift in agro-climate which affects temperate crops. The production of corn and maple is now limited. In Tanzania, Africa, the climate has improved the production of maize and rice. In Australia, severe drought has transformed agriculture as the farmers switch the production of rice for the production of wine grape. Wheat production is devastated in the Indo-Gangetic Plain, so India and Pakistan are back in wheat deficit. Barley production is supported in New Zealand and Australia while it is being driven to extinction in Ethiopia. In the past 2 years, the weather has supported increased production of soybean in Brazil. In 2008, malnutrition dropped significantly in Niger Republic due to increased harvests of rain-fed grain crops. In the same year the weather favoured the production of grains in Nigeria but in Somalia, localized flood event destroyed late maize crop. Flood events at continental level affected the regions ofEthiopia, Somalia and Kenya and caused significant loss of livestock. In Asia, Afghanistan lost farmland, livestock and mills to heavy rains and flood. Central and Eastern Europe lost huge hectares of farmland with Hungary losing more land area to flood water. The Great Plains of North America lost huge area of farmland as Red River flowed over in 2006. The tributaries of River Amazon in Brazil and three states in Argentina covering250,000 km2 along the river basin was lost to flood. An epidemic re-emerged in Angola in the wake of a flood event in 2006. A mitigation of the effects of global warming should include a stable, democratic government and the presence of basic infrastructure in the developing countries. Techniques, which are applicable to traditional and small scalefarming systems are required. Research works that evolve mitigation techniques should be advocated and funded; and findings of research disseminated to the farmers. There is need to develop crops which are resilient to drought and water logging. Research in plant and animal diseases must be vigorous and well funded. Adaptive techniques consistent with change in the climate of each region seem the solution to world food security. A shift in agricultural trade pattern is certain and important to correct the climate change anomalies in agricultural output and food production across the world. Mitigation efforts must be initiated by governments and must start at the grass root.Keywords: Global Warming Impact, Food Security

THE EFFECT OF ALGAEGREEN 200 (COLD-PROCESS SEAWEED LIQUID EXTRACT) ON THE MINERAL CONTENT OF 'BRAMLEY'S SEEDLING' APPLE LEAVES AND FRUIT

ISHS VI International Symposium on Mineral Nutrition of Fruit Crops THE EFFECT OF ALGAEGREEN 200 (COLD-PROCESS SEAWEED LIQUID EXTRACT) ON THE MINERAL CONTENT OF 'BRAMLEY'S SEEDLING' APPLE LEAVES AND FRUIT

Herbicide tolerant canola systems and their impact on winter crop rotations

Canola is widely grown in Australia to provide diversity within winter crop rotations. Its production is heavily reliant on triazine tolerant varieties but Clearfield ® and conventional varieties are also significant components of the industry. Glyphosate tolerant varieties have been introduced, thereby providing an alternative technology to be incorporated into the farming systems. To evaluate the potential impact of the relative herbicide technologies, a comparison of herbicide tolerant canola weed management systems was undertaken at Wagga Wagga, Australia over a 5-year rotation. Near isogenic lines of conventional, glyphosate tolerant and triazine tolerant varieties were evaluated for their abilities to control annual ryegrass ( Lolium rigidum), the most challenging weed of temperate crops in Australia. Glyphosate tolerant and triazine tolerant canola achieved high levels of ryegrass control and attained higher yields than the conventional system. Glyphosate tolerant canola provided extra control of broadleaf weeds and also achieved better seed oil levels when compared with the other canola systems. There were positive flow-on weed management benefits for the remainder of the crop sequence from the weed control achieved in the initial crop, particularly following glyphosate tolerant canola. Subsequent control of volunteer canola in all treatments was readily achieved by using paraquat/diquat. The glyphosate tolerant weed management system was more profitable than the triazine tolerant system, although no allowance was made for technology costs as they were not known at the time of study. These outcomes demonstrate the potential value of herbicide tolerant canola to Australian farmers.

A carbon sequestration strategy involving temperate fruit crops in the trans-Himalayan region

SummaryA current major concern is increasing levels of atmospheric CO2 which may be responsible for global warming or climate change. Fruit tree orchards have received attention in recent years by virtue of their potential to act as carbon pools. The trans-Himalayan valley (i.e., the Nubra Valley) at an altitude of 3,048 m, is covered by > 60,000 temperate fruit trees. The focus of this paper is on the potential of these fruit-yielding trees as a means of carbon sequestration in the Nubra Valley. The valley produces approx. 4,650 metric tonnes (MT) of apricot, apple, walnut, mulberry, grape, and plum fruit. It was observed that the total biomass of the temperate fruit trees (i.e., apricot, apple, and walnut) in the area surveyed was 40,000 MT dry weight (DW). Thus, 22,300 MT of carbon has been sequestered by these fruit species. This study revealed that the cultivation of temperate fruit crops species such as apricot, apple, and walnut could be exploited more efficiently for carbon sequestration which subsequently helps in mitigating global CO2 levels and restoring degraded land in these cold, arid areas by improving soil organic carbon (SOC) contents. These results concluded, in part, that growing biomass to sequester carbon is a beneficial grow-and-store process for sustainable development.

THE GENOMICS OF FRUIT QUALITY

Consumers of whole foods, such as fruits, demand consistently high quality and the development of new varieties with enhanced health, convenience, novel taste, and a reduced impact on the environment. Conventional breeding of temperate fruit crops such as apples and kiwifruit, the focus of HortResearch, exploits both existing cultivars and the extensive germplasm collections of related species and novel accessions. Our genomics research is focused on the key producer and consumer traits. We achieve this by defining the biology of our key fruit traits and developing an understanding of the processes in model plants. Our translation genomics research then transfers this molecular information to our target crops. To do this, we have developed an extensive fruit EST sequence database and are in the process, through collaboration, of developing a Whole Genome Sequence for these crops. In our work on fruit colour, we have described both the metabolic and regulatory genes involved in anthocyanin accumulation, through sequencing and functional conservation with genes from model plants.

Climate change and prolongation of growing season: changes in regional potential for field crop production in Finland

Climate change offers new opportunities for Finnish field crop production, which is currently limited by the short growing season. A warmer climate will extend the thermal growing season and the physiologically effective part of it. Winters will also become milder, enabling introduction of winter-sown crops to a greater extent than is possible today. With this study we aim to characterise the likely regional differences in capacity to grow different seed producing crops. Prolongation of the Finnish growing season was estimated using a 0.5º latitude × 0.5º longitude gridded dataset from the Finnish Meteorological Institute. The dataset comprised an average estimate from 19 global climate models of the response of Finnish climate to low (B1) and high (A2) scenarios of greenhouse gas and aerosol emissions for 30-year periods centred on 2025, 2055 and 2085 (Intergovernmental Panel on Climate Change). Growing season temperature sums that suit crop growth and are agronomically feasible in Finland are anticipated to increase by some 140 °Cd by 2025, 300 °Cd by 2055 and 470 °Cd by 2085 in scenario A2, when averaged over regions, and earlier sowing is expected to take place, but not later harvests. Accordingly, the extent of cultivable areas for the commonly grown major and minor crops will increase considerably. Due to the higher base temperature requirement for maize (Zea mays L.) growth than for temperate crops, we estimate that silage maize could become a Finnish field crop for the most favourable growing regions only at the end of this century. Winters are getting milder, but it will take almost the whole century until winters such as those that are typical for southern Sweden and Denmark are experienced on a wide scale in Finland. It is possible that introduction of winter-sown crops (cereals and rapeseed) will represent major risks due to fluctuating winter conditions, and this could delay their adaptation for many decades. Such risks need to be studied in more detail to estimate timing of introduction. Prolonged physiologically effective growing seasons would increase yielding capacities of major field crops. Of the current minor crops, oilseed rape (Brassica napus L.), winter wheat (Triticum aestivum L.), triticale (X Triticosecale Wittmack), pea (Pisum sativum L.) and faba bean (Vicia faba L.) are particularly strong candidates to become major crops. Moreover, they have good potential for industrial processing and are currently being bred. Realisation of increased yield potential requires adaptation to 1) elevated daily mean temperatures that interfere with development rate of seed crops under long days, 2) relative reductions in water availability at critical phases of yield determination, 3) greater pest and disease pressure, 4) other uncertainties caused by weather extremes and 5) generally greater need for inputs such as nitrogen fertilisers for non-nitrogen fixing crops.;

Brachypodium Genomics

Brachypodium distachyon (L.) Beauv. is a temperate wild grass species; its morphological and genomic characteristics make it a model system when compared to many other grass species. It has a small genome, short growth cycle, self-fertility, many diploid accessions, and simple growth requirements. In addition, it is phylogenetically close to economically important crops, like wheat and barley, and several potential biofuel grasses. It exhibits agricultural traits similar to those of these target crops. For cereal genomes, it is a better model than Arabidopsis thaliana and Oryza sativa (rice), the former used as a model for all flowering plants and the latter hitherto used as model for genomes of all temperate grass species including major cereals like barley and wheat. Increasing interest in this species has resulted in the development of a series of genomics resources, including nuclear sequences and BAC/EST libraries, together with the collection and characterization of other genetic resources. It is expected that the use of this model will allow rapid advances in generation of genomics information for the improvement of all temperate crops, particularly the cereals.

Adana ilinde bazı ılıman iklim meyvelerinde iki thrips (Thysanoptera) türünün populasyon değişimleri ve zararı üzerine araştırmalar

1Summary Population fluctuations of two thrips (Thysanoptera) species and the thrips damage associated with some temperate fruits in Adana province, Turkey In this study, the population fluctuations of two common thrips species, Frankliniella occidentalis (Pergande) and Thrips major Uzel (Thysanoptera:Thripidae), and the thrips damage associated with temperate fruit crops, plum (Prunus domestica), apple (Malus domestica) and nectarine (Prunus persicae var nectarina) were examined in Adana between 2007-2008. T. major was the predominant thrips on apple flowers, while adult F. occidentalis were more abundant on the flowers of plum and nectarine. The mean numbers of adults of both thrips peaked in the flowers of trees at the beginning of petal fall (end of March) and thereafter their numbers decreased to low levels. Mean numbers of larval thrips increased to peak levels at the period between petal fall and forming of fruits. Numbers of adults and immature thrips were very few at the maturation periods of fruits. F. occidentalis was the main thrips species causing economically important damage on crops. It caused scarring and silvering damage on the fruits. Damage on the unripe fruits of plum and nectarine were detected after occurrence of average two adults per flower and 4-8 larval thrips per fruit. This damage symptoms on fruits (7-15 days old) is mainly due to attacks of larval thrips. In 2007 scarring ratio in apple, plum and nectarine fruits was 5%, 30% and 29 % respectively. In 2008, there was no thrips on the apple fruits, 1% and 9%, of plum and nectarine fruits were scarred.

Effects of irrigation and straw mulch on water use and tuber yield of potato in eastern India

Potato, being a temperate crop, its growth and tuber production are limited by high atmospheric temperatures (mean temperature >17 °C). As a result potato is grown in winter season only (November–March) in the eastern plain of India when temperature is favourable. But during winter season, rainfall is erratic and meagre, therefore, potato crop in the region can only be grown with supplemental irrigation. In this study, potato crop was grown with four phenology based irrigation treatments (75 mm water depth with each irrigation) with three replications. Straw mulch at a rate of 6 t ha −1 was applied during the first earthing up in half of the plots to observe the variation of plant growth, water use efficiency and tuber production between mulched and non-mulched plots. The experimental split-plot design consisted of irrigation treatments in the main plots with mulching and non-mulching as subplots. Two years of pooled data with four irrigations resulted in air-dry tuber yields of 14.9 and 11.2 t ha −1 for the mulched and non-mulched plots, respectively. Significantly ( p < 0.05) higher leaf area index, water use efficiency and intercepted photosynthetically active radiation (IPAR) were recorded in the mulched plots compared to the non-mulched plots under the same irrigation treatment. Higher yield and better crop growth were observed in the mulched plots, which might be due to conservation of soil moisture and reduction of soil temperature by 4–6 °C. The highest PAR (89% of the PAR incident above the crop canopy) was found near the crop with mulching and four irrigations. The 77–103 mm less depleted soil moisture in the different treatments was due to the application of straw mulch. Application of straw mulch significantly increased the available phosphorus and potassium in the soil. Water use efficiency and tuber productions differed significantly among irrigation treatments in the non-mulched plots but they did not in the mulched plots with three and four irrigations. Therefore, three irrigations of 75 mm each and mulching were recommended for growing potato in the region when limited water was available.