Grain-filling Period Research Articles

Drought Stress in Wheat during Flowering and Grain-filling Periods

Drought is a major environmental stress threatening wheat productivity worldwide. Global climate models predict changed precipitation patterns with frequent episodes of drought. Although drought impedes wheat performance at all growth stages, it is more critical during the flowering and grain-filling phases (terminal drought) and results in substantial yield losses. The severity and duration of the stress determine the extent of the yield loss. The principal reasons for these losses are reduced rates of net photosynthesis owing to metabolic limitations—oxidative damage to chloroplasts and stomatal closure—and poor grain set and development. A comprehensive understanding of the impact of terminal drought is critical for improving drought resistance in wheat, with marker-assisted selection being increasingly employed in breeding for this resistance. The limited success of molecular breeding and physiological strategies suggests a more holistic approach, including interaction of drought with other stresses and plant morphology. Furthermore, integration of physiological traits, genetic and genomic tools, and transgenic approaches may also help to improve resistance against drought in wheat. In this review, we describe the influence of terminal drought on leaf senescence, carbon fixation, grain set and development, and explain drought resistance mechanisms. In addition, recent developments in integrated approaches such as breeding, genetics, genomics, and agronomic strategies for improving resistance against terminal drought in wheat are discussed.

Genetic and Molecular Analysis of Transgenic Rice cv. Rojolele Expressing Lactoferrin

In a previous study, human lactoferrin gene have introduced into Javanica rice cv. Rojolele by Agrobacterium-mediated transformation. Lactoferrin (LF) is an 80 kDa iron-binding glycoprotein that has been proposed to have many biological roles such as protection against microbial and virus infection. This study aims to analyze the integration and level of lactoferrin gene expression of transgenic rice cv. Rojolele. The study also aims to examine the genetic character of transgenic rice expressing recombinant lactoferrin. Stability expression of recombinant lactoferrin transgenic rice seeds over generations were analyzed by ELISA, while the integration stability of recombinant hLF gene in transgenic plants performed by PCR. The mitotic time, cell cycle and chromosome characterization of transgenic and non-transgenic rice cv. Rojolele were determined. Chromosome characterization of the trangenic and non transgenic rice cv. Rojolele was investigated to determine the genetic variation. All of the above efforts were aimed to evaluate the genetically engineered rice containing recombinant lactoferrin as a nutraceutical food. The results showed that the expression was stable through three consecutive generations. The expression of the hLF gene increased during grain-filling period. The active time of mitotic cells of transgenic rice rojolele was longer than the cells of non-transgenic rice. In addition, the cycle cell of transgenic and non-transgenic rojolele contained prophase, prometaphase, metaphase, anaphase, telophase and interphase. The result showed that all of the transgenic lines had diploid (2n) chromosome number = 24.

Monitoring Nitrogen Leaf Resorption Kinetics by Near‐Infrared Spectroscopy during Grain Filling in Durum Wheat in Different Nitrogen Availability Conditions

ABSTRACTIn wheat (Triticum spp.), the N content of leaves during the grain filling period (GFP) plays a key role in maintaining photosynthetic activity and determining the amount of N available for grain protein content (GPC). We documented flag N leaf resorption in durum wheat (Triticum turgidum L.) plants under a nonlimiting level of N in 2010 and under two different levels of N fertilization in 2011. During the GFP, we monitored changes in flag leaf N content by a nondestructive method based on near‐infrared spectroscopy. The datasets were modeled for each plant; parameters were extracted and analyzed to determine which source of variation (genotype and/or N availability) predominated. Different genotypic profiles were highlighted opposing Ixos versus Primadur when comparing two different levels of N availability, with Ixos flag leaves being the most affected by a low level of N preanthesis. High postanthesis N availability delayed the beginning of N resorption (t0) and there was a strong negative correlation between t0 and the resorption duration. Delayed N resorption was associated with better grain yield components. A high proportion of the variation of grain yield per spike and GPC was explained by multiple linear regressions combining the width of the flag leaf and N dynamic parameters under the nonlimiting N availability. The negative correlation between yield and GPC may result from the initiation of N resorption during grain filling, potentially increasing yield if delayed or increasing GPC if occurring early.

Difference of Characteristics of Photosynthesis, Matter Production and Translocation between Indica and Japonica Super Rice

This study was to reveal the difference of characteristics of dry matter accumulation and photosynthetic production between indica and japonica super rice. Field experiments were conducted by using five representative super hybrid indica combinations and five conventional japonica super rice varieties planted on a large scale in Jiangsu region with rice-wheat double cropping rotation. Dry matter accumulation, distribution and translocation, leaf area, leaf area duration(LAD), crop growth rate(CGR), net assimilation rate(NAR), seedling quality and leaf type were analyzed systematically. Results showed that, dry matter accumulation, LAD, CGR, and NAR at the early growth stage(from transplanting to jointing), leaf length, leaf base angle, angle between stem and leaf and drooping angle in top three leaves, leaf area decreasing per day after heading and harvest index of japonica rice were less than those of indica rice significantly, while dry matter accumulation, LAD, CGR, and NAR at the middle and later growth stages(from jointing to maturity), ratio of leaf area of productive tillers, ratio of leaf area of top three leaves, grain-leaf ratio(spikelets per cm2 leaf area, filled grains per cm2 leaf area and grain weight per cm2 leaf area), maximum leaf area index, total filling, grain yield, biological yield, maximum output and apparent output and their ratio were larger than those ofindica rice significantly. Although dry matter weight per stem of japonica rice at the main growth stages was lower than that of indica rice, the superiority of population quantity suggested that japonica rice would possess higher dry matter accumulation and leaf area. With the advancement of growth and development, the superiority of photosynthesis and matter production of japonica rice was increasing, with a higher dry matter accumulation more than that of indica rice 25 d after heading approximately. The growth potential of japonica rice remained strong at the late period of grain-filling(from milky stage to maturity), while stored matter kept in the stem and sheath exported appropriately at the early period of grain-filling(from heading to milky stage), ensuring the security of efficient photosynthetic layer and the enrichment of high accumulation yield sink. Therefore, balanced formation of high biological yield, stable-increasing-slow-decreasing tendency of leaf area, and the large amounts of high efficient photosynthate production from jointing to maturity are the important characteristics and causes for the efficient and sustainable output of photosynthetic systems, more grain-filling and high yield formation in japonica rice.

Developing selection criteria based on an ontogenetic path analysis approach to improve grain yield in barley.

We used correlation and path coefficient analysis based on an ontogenetic approach to develop selection criteria in barley (Hordeum vulgare L.) for an early production system in Ethiopia. A total of 100 genotypes using 10x10-simple lattices with two replications were used to perform the experiment at Ambo and Asasa. The combined analysis of the measured traits showed significant differences among genotypes for all traits. A positive correlation was observed between grain yield and spike/m2, kernel number/spike, and 1000-kernel weight. The path analysis showed that spike/m2, 1000-kernel weight, and kernel number per spike had significant positive direct effects on grain yield, which shows that these traits can be used as selection criteria to improve grain yield. The significant positive correlation of spike/ m2, 1000-kernel weight, and grain-filling period and the positive direct effect on grain yield indicated the potential of these traits as indirect selection criteria to improve grain yield in the early production system in Ethiopia. This study also showed that the path coefficient analysis based on an ontogenetic model was efficient and produced results that can be interpreted clearly.

Relationship between the Rice Grain Quality and Chlorophyll Meter Values (SPAD Values) during Grain-Filling Period in Miyagi Prefecture

Relationship between the Rice Grain Quality and Chlorophyll Meter Values (SPAD Values) during Grain-Filling Period in Miyagi Prefecture

Effects of Shading on Grain-Filling Properties and Yield of Maize at Different Growth Stages

The objective of this study was to explore the effect of shading at different growth stages on grain filling properties and yield of maize(Zea mays L.). The Field experiments were carried out using maize cultivars(Jingke 968, Zhengdan 958) with shading of 50% at the 13 th leaf fully expanded(T1), the silking(T2) and the15 th day after silking(T3) for seven days in 2012–2013. The natural light condition without shading was used as the control. The Logistic equation was used to analyze the grain filling process. The results showed that grains per ear, 1000-kernel weight and yield were all decreased to a different degree under shading conditions at different growth stages, and the decrease rate of grain yield was increased with lasting shading duration. The yield was significantly different under different shading treatments. The duration of the maximum grain filling and active grain-filling period(P) were shortened, the maximum and mean grain-filling rate(Gmax) decreased and the final grain weight(A) reduced under shading conditions. The relation among grain weight, grain number per ear and grain yield was determined by characteristics of maize cultivar. The grain weight of the same cultivar was significantly positively correlated with grain weight with the maximum grain-filling rate(Wmax), and the grain weight of different maize cultivars was determined by active grain-filling period(P). The grain number per ear of the same maize cultivar was significantly positively correlated with Gmax, and the grain number per ear of different maize cultivars was determined by Wmax. It is an important way to keep a high or stable yield by selecting the suitable cultivar, improving Wmax and Gmax and prolonging active grain-filling period(P) under weak light stress.

Effect of genotypic, meteorological and agronomic factors on the gluten index of winter durum wheat

The determination of the gluten index is a widely used method for analysing the gluten strength of bread wheat and spring durum wheat genotypes. The present work was carried out to study the effect of the genotype, meteorological factors (temperature, precipitation and number of days with Tmax ≥ 30 °C) and agronomic treatments (N fertilisation and plant protection) on the gluten index of winter durum wheat varieties and breeding lines. The results indicated that the gluten index had little dependence on the environment, being determined to the greatest extent by the genotype. Compared with varieties having weak gluten, those with a strong gluten matrix responded less sensitively to changes in environmental conditions. Among the meteorological factors, high temperature at the end of the grain-filling period caused the greatest reduction in the mean gluten index of three varieties (R 2 = 0.462), while the fertiliser was found to be a significant factor affecting the gluten strength of winter durum wheat varieties. Using selection based on the gluten index, the gluten strength of winter durum wheat lines can be improved sufficiently to make them competitive with high quality spring varieties.

Post-Anthesis Drought Management in Late-Shown Wheat (Triticum aestivum)

Post anthesis drought is common problem in late sown wheat, which reduces crop yield. A field experiment was conducted at Institute of Agriculture and Animal Science (IAAS), Rampur in 2005/06 to find out the effect of irrigation, seed rate and mulch on soil moisture content and productivity of late sown wheat. Irrigation applied at crown root initiation CRI and heading stage significantly increased moisture content at 80 days after sowing, grain filling period (GFP) and crop duration period (CDP), thousand grain weight, grain yield and harvest index. Higher seed rate was non significant on yield attributes and yield. Soil moisture content at 30, 80 and 95 days after sowing, vegetative growth period (VGP) and crop duration period, and grain yield were significantly higher in mulched plot than non mulched plot. Irrigation at reproductive stage and mulch were effective in increasing yield of late sown wheat.

Slow-release fertilizer to increase grain N content in spring wheat

Low grain protein often restricts the use of grain lots for milling in Finland. Nitrogen availability during grain-filling may restrict grain protein accumulation, particularly in high yielding environments. Slow-release fertilizers could potentially sustain nitrogen availability during the grain-filling period. The aim of this study was to increase plant nitrogen uptake, grain yield and grain protein response of spring wheat cultivar ‘Amaretto’, using combinations of a regular and slow-release compound NPK fertilizer. Fertilizer treatment effects on grain yield was modest, however, slow-release fertilizer treatments lowered grain protein content as well as grain, straw and total plant N compared with control treatment. The total plant N was 10 to 27 kg ha-1 lower following application of slow-release fertilizer. The results clearly indicate that the release of N by the slow-release fertilizer tested in this trial was too slow for cool Finnish growing conditions.

イネコアコレクションにおける登熟期高温下 stay green 品種

イネコアコレクションにおける登熟期高温下 stay green 品種

Effect of PASP-KT-NAA on Leaf Senescence and Grain Filling Rate during the Grain-Filling Period in Different Temperature Zones

A field experiment was performed to investigate the effects of the chemical regulation of PASP-KT-NAA(PKN)on leaf senescence physiology and grain filling rate under different temperatures.The result showed that the activities of superoxide dismutase(SOD),peroxidase(POD),catalase(CAT),chlorophyll concentration in ear leaves of two maize cultivars were declined, while malondialdehyde(MDA)content increased in three accumulate temperature zones with low temperature.In the same accumulated temperature zone,and in process of growth,SOD,POD,CAT activities showed the trend of a single peak curve with "first increase and then decrease",and MDA content showed an opposite trend.PKN treatment increased SOD,POD,CAT activities and chlorophyll contents of ear leaves,while declined MDA content in ear leaves of Zhengdan 958 and Fengdan 3.From the first accumulated temperature zone to the third accumulated temperature zone,the grain weight of two maize cultivars show a S-shape increase in the"low-fast-low"type and the grain filling rate showed an"increased and then declined"trend.The grain weight and the grain filling rate of the first accumulated temperature zone were higher than those of the second and the third accumulated temperature zones.PKN treatment had higher grain weight and the grain filling rate compared with the control.In 2010 and 2011,the yield of two varieties of maize increased in the PKN treatment.The yield of Zhengdan 958 and Fengdan 3 in the third accumulated temperature zone were 2.58%,1.17%and 2.04%,1.48%higher than those in the first and second accumulated temperature zones,in 2010 and 8.2%,5.1%and 3.4%,0.8%higher than those in the first and second accumulated temperature zones in 2011.Thus,the chemical regulation was proved to be useful to delay the leaf senescence,improving the grain filling rate,and ultimately increasing the yield in maize.

SOURCE-SINK MANIPULATION EFFECTS ON MAIZE KERNEL QUALITY

Evaluation of source or sink limitations on maize (Zea mays L.) yield and yield components is important for the rational design of agricultural practices as well as breeding strategies. There is little information on how the source or sink limitations during the effective grain-filling period affect final kernel quality. The objective of this study was to evaluate the effect of source/sink manipulation in different times after mid-silking stage on kernel weight (KW), kernel number per square meter (KN m−2), kernel protein and oil of different maize hybrids. Field experiments were conducted at the experimental field of College of Agriculture, Shiraz University, Shiraz, Iran, located at Bajgah (52° 35′ N and 39° 4′ E and 1810 m above sea level, asl) during the 2008 and 2009 growing seasons. The treatments included three hybrids and defoliation that were arranged in the main, and subplots, respectively. Leaves removal treatments were imposed when plants were at the mid-silking stage. Silking was taken as the time when 50% of the plants in a row presented visible silks. Defoliations included control, 50% of defoliation at 25 (early defoliation), and 35 (late defoliation) days after silking (defoliation treatments were applied to all plants of each plot). The experiments were conducted in randomized complete block (RCB) design with three replications and the treatments in a split-plot arrangement. Early defoliation greatly reduced kernel growth rate and grain filling period, resulting in lower mean kernel weight. Defoliation treatments modified KN m−2 and kernel number per ear (KNPE) and variations in these components affected protein and oil content. Decreased source size by defoliation decreased kernel protein content dramatically with no significant change in oil content. Differences among treatments appeared to be related only to the post-flowering source/sink ratio. Therefore, to improve protein yield in maize, hybrids and agronomic practices should aim to increase the post-flowering source/sink ratio.

Re-examination of the standard cultivation practices of rice in response to climate change in Korea

The impact of climate change has been simulated or estimated to bring about yield decline and quality deterioration of rice in Korea, a temperate country. To cope with these negative impacts, here we propose likely changes in the standard cultivation practices of rice in consideration of the current information on the progress/prediction of climate change and related physiological aspects of rice. Shifting grain-filling period could be a promising choice to optimize temperature for rice grain-filling, a crucial growth stage to productivity, hence providing rice plants with sufficient duration and solar radiation for the period. This choice, however, shortens days to flowering by the additive combined effects of high temperature by delayed transplanting, temperature rise itself by climate change, and accelerated phase change of rice by high temperature and short day-length. These combined effects may delay the time of transplanting in a great extent, hence reducing biomass accumulation of rice before flowering. In these conditions, recovering decreased biomass production is the key concern for rice productivity. This includes raising healthy seedlings by omitting the covering process, dense planting, and nutrient management to enhance plant’s uptake activity. Current standard water management, especially mid-term drainage and intermittent irrigation, would have more importance in the future since they mitigate methane emission from the paddy. Field monitoring for weeds and pests would be an important first step to identify newly developing or thriving species for establishing subsequent controlling strategies. Earlier weed control should be emphasized through adjusting time of herbicide application.

Grain-filling patterns and nitrogen utilization efficiency of spelt (Triticum spelta) under Mediterranean conditions

SUMMARYThe identification of factors determining the adaptation and nitrogen (N) utilization of spelt wheat is important for the successful introduction of the crop to a new environment. The present study was carried out to investigate the relative importance of grain-filling rate and duration of grain growth and to analyse the nitrogen utilization efficiency (NUtE) and biomass production efficiency of spelt under Mediterranean conditions. The performance of spelt was evaluated in relation to a well-adapted bread wheat cultivar. Three spelt cultivars (Ressac, Poème and Cosmos) and one bread wheat cultivar (Centauro) were grown for two growing seasons on a silty clay soil under two N levels (0 and 100 kg N/ha). Grain-filling parameters were estimated using the cubic polynomial model. This model provided good fit to the grain-filling data of spelt cultivars, with high coefficients of determination (R2) that ranged from 0·868 to 0·999. Cultivar differences were found for all grain-filling parameters studied, and these differences accounted for most of the variation observed within each particular grain-filling component in both years. Grain filling of spelt plants took place under adverse environmental conditions, mainly high temperatures, which led to a shortening of the grain-filling period. This fact was not fully compensated by the increase in the grain-filling rate, and eventually resulted in a reduction of the final spelt grain weight. Selection for early-flowering cultivars could be a successful strategy to moderate the influence of the environment on grain filling and improve the adaptation of spelt under Mediterranean conditions. The mean grain-filling rate was positively correlated with dry matter translocation, suggesting the crucial role of reserve assimilates in the vegetative tissues for the grain growth of spelt. The efficiency of N utilization to produce biomass was greater during the grain-filling period than the vegetative period. Averaged across N application rates, NUtE in spelt ranged from 20·1 to 29·5 g grain/g plant N. Cultivar differences in NUtE were observed in both years. Grain yield per unit grain N (grain DM/grain total N at maturity) contributed more to the total variation in NUtE among spelt cultivars compared with N harvest index (NHI). Spelt showed lower NUtE values, probably due to its higher grain N concentration and lower NHI compared with wheat. Low straw N concentration at maturity may be an indicator of improved NUtE in spelt, as evidenced by the negative relationship detected between the two variables. These results provide a better understanding of factors related with the adaptation and N utilization of spelt under Mediterranean conditions.

Evaluation of the yield and baking quality of winter wheat (Triticum aestivum L.) varieties in different cropyears

We have investigated the effect of the cropyear, the genotype, the nutrient supply and their interactions on the yield and the quality parameters of three different winter wheat genotypes in three different cropyears. The most disadvantageous influence on the yield averages was caused by the moist weather of 2010, when yield results fell behind the mean of the two other examined years and the nutrient optimum was around low doses. The optimal cropyear turned out to be the ordinary 2011, the best yield results were experienced during this cropyear. Although the drier periods in 2012 decreased the yield values, the varieties could realize high yield maximum values. Considering the yield results, Genius turned out to be the best variety. In respect of the quality traits, 2010 turned out to be the best cropyear in case of all the three varieties. Despite the dry weather of the spring of 2012, the precipitation fell during flowering and ripening phases had positive impact on the grain-filling processes and contributed to the development of better quality. As a consequence of the significantly lower amount of precipitation during the generative phenological phases, the worst quality parameters were realized by the varieties in 2011.
 
 In respect of crop year effect, 2010 was unfavourable for the amount of yield, but the most beneficial for the quality. 2011 was the most advantageous for the yield amounts but disadvantageous for the quality parameters. Although in 2012 extreme crop year effects were experienced after each other (dry and warm spring, moist and warm summer), the yield average and quality trait values were close to the yield averages of 2011 and quality parameters of 2010. Analyzing our results we can state that the average crop year was favourable rather for the yield. The appropriate amount of precipitation during the whole 2010 and that during the generative phenophases in 2012 favoured the development of good quality.
 Consequently, the appropriate amount of precipitation is essential for the development of good quality during the grain-filling period. The negative crop year effects were only compensated but not eliminated by the good nutrient supply. Genius achieved excellent yield averages but performed worse quality parameters than Mv Toldi, whose quality parameters were outstanding but the yield averages fell slightly behind those of Genius. Considering the yield results, the variety Genius turned out to be the best, while Mv Toldi was the best in quality.

Identification of the chromosomal region responsible for high-temperature stress tolerance during the grain-filling period in rice

An unusually high temperature during the grain-filling period, such as that caused by global warming, impairs the quality of rice (Oryza sativa L.) grains. This sensitivity to high-temperature stress is different among cultivars, suggesting the possibility of developing a high-temperature-tolerant cultivar. Since marker-assisted selection would reduce time and labor in breeding for such a quantitative trait, we determined the chromosomal region responsible for high-temperature tolerance during the grain-filling period. A high-temperature-sensitive japonica cultivar Tohoku 168 and a tolerant japonica cultivar Kokoromachi were selected as the parental lines of recombinant inbred lines (RILs) by high-temperature stress treatment from 5 to 10 days after anthesis, which was found to be the period most critical for grain quality. Using the RILs, whose genotypes were determined by analysis with 131 DNA markers which were selected as polymorphic markers between these two cultivars from 2,648 DNA markers tested, the quantitative trait locus (QTL) for the percentage of white-back grains was mapped on chromosome 6. The Kokoromachi allele of the QTL, which had a positive additive effect on the high-temperature tolerance, was introduced into the Tohoku 168 genome by repeated backcrossings with marker-assisted selection. Using high-temperature stress treatment of the near isogenic lines developed, the QTL on chromosome 6 was localized within a 1.9-Mb region between two DNA markers, ktIndel001 and RFT1. These DNA markers would be useful not only for breeding high-temperature-tolerant cultivars but also for map-based cloning of the QTL.

Comparative behavior of wheat and barley associated with field release and grain weight determination

Double-cropping using the wheat–soybean sequence is a common practice in Argentina to promote the intensification of crops within rotations. However, the late release of the fields by a delayed harvest time in wheat determines soybean yield penalizations. In this context, barley could represent a better option than wheat preceding soybean in the crop rotation since there is some evidence that finishes its cycle earlier than wheat. However, it is not clear which period of barley shortens crop cycle allowing an earlier field release than wheat. The objectives of this study were to compare wheat and barley in terms of (i) field release and (ii) grain weight determination through the analysis of their physiological mechanisms. Field experiments during two consecutive growing seasons testing five different environments (three sowing dates in 2007 and two in 2008) were carried out to analyze the duration of different ontogenic periods and the attributes (dry matter and water dynamics) determining grain weight during the grain-filling period in wheat and barley. Early flowering time was the main cause of the early field release by barley as the grain filling and drying period were similar in both species. A strong relationship was found between dry matter and water dynamics in both species. Barley reached a higher maximum water content than wheat and also achieved physiological maturity with higher moisture concentration than wheat (48% and 39%, respectively). Barley showed a slight increase in grain weight, respect to wheat, due to a source:sink ratio enhancement (4% and 9% for wheat and barley, respectively). These data show an opposite response to that of Mediterranean, Australian and UK environments, where barley was under stronger sink limitation than wheat during the grain-filling period.

Identification of quantitative trait loci for flowering-related traits in the D genome of synthetic hexaploid wheat lines

The gene pool of Aegilops tauschii, the D-genome donor of common wheat (Triticum aestivum L.), can be easily accessed in wheat breeding, but remains largely unexplored. In our previous studies, many synthetic hexaploid wheat lines were produced through interspecific crosses between the tetraploid wheat cultivar Langdon and various A. tauschii accessions. The synthetic hexaploid wheat lines showed wide variation in many characteristics. To elucidate the genetic basis of variation in flowering-related traits, we analyzed quantitative trait loci (QTL) affecting time to heading, flowering and maturity, and the grain-filling period using four different F2 populations of synthetic hexaploid wheat lines. In total, 10 QTLs located on six D-genome chromosomes (all except 4D) were detected for the analyzed traits. The QTL on 1DL controlling heading time appeared to correspond to a flowering time QTL, previously considered to be an ortholog of Eps-A m 1 which is related to the narrow-sense earliness in einkorn wheat. The 5D QTL for heading time might be a novel locus associated with wheat flowering, while the 2DS QTL appears to be an allelic variant of the photoperiod response locus Ppd-D1. Some of the identified QTLs seemed to be novel loci regulating wheat flowering and maturation, including a QTL controlling the grain filling period on chromosome 3D. The exercise demonstrates that synthetic wheat lines can be useful for the identification of new, agriculturally important loci that can be transferred to, and used for the modification of flowering and grain maturation in hexaploid wheat.

Genotype × Environment × Management: Interactions Key to Beating Future Droughts

Genotype × Environment × Management: Interactions Key to Beating Future Droughts