High Kernel Weight Research Articles

Differential analysis and genome-wide association analysis of stomata density of maize inbred lines leaves at ear position

The stomatal complex on the surface of maize leaves is closely related to photosynthesis and transpiration, and the study of maize stomatal phenotypes and the discovery of their regulatory genes are of great importance for the breeding of high-quality and high-yielding maize. In this study, rapid scanning electron microscopy was used to obtain images of the abaxial stomata of 457 maize inbred lines with extensive genetic variation, and stomata density was obtained by counting. The results of correlation showed that stomata density was significantly correlated with leaf width, and Analysis of variance found that there were significant differences ( P value < 0.05) in stomata density among different leaf width and 100-grain weight. The highest stomata density was found in the inbred lines with wide and short leaves and higher 100-grain weight. Furthermore, genome-wide association analysis was performed using a mixed linear model. It showed that eight SNPs significantly associated with stomata density were obtained, which could explain 35.507% of the phenotypic variation. Among these, four SNPs on chromosome 5 were tightly linked, mainly formatting two haplotypes, CTTA (0.636) and TCCG (0.330). Twelve genes with functional annotation were identified within 100 kb upstream and downstream of the eight SNPs. One gene, GRMZM2G068277, which had been shown to be involved in plant mitotic processes and exhibited high expression at the leaf base, was therefore the most likely candidate gene for stomata density. The results presented here could provide references for further cloning of functional genes related to stomata density.

Fine mapping of KLW1 that conditions kernel weight mainly through regulating kernel length in wheat (Triticum aestivum L.).

KLW1 was localized to a 0.6 cM interval near the centromere of chromosome 4B and found to be dominant in conditioning longer kernels and higher kernel weight. Kernel weight is a major wheat yield component and affected by kernel dimensions, filling process and kernel density. Because of this complexity, the mechanism underlying kernel weight is still far from clear. Qtgw.nau-4B or KLW1 was a major kernel weight QTL identified in the Nanda2419 × Wangshuibai population. We showed that introduction of the Nanda2419 allele into elite cultivar Wenmai6 resulted in longer kernels as well as higher kernel weight, without affecting other traits such as spike number per plant, plant height, spike length, spikelet number per spike, and kernel number per spike. KLW1 was dominant in conditioning higher kernel weight and functioned mainly through affecting kernel length. Using F2 plants derived from KLW1 NIL, a high-density genetic map covering the QTL was constructed. KLW1 was consequently confined to the 0.6cM Xwgrc4219-Xwgrc4067 interval by evaluating the recombinant lines in three field trials. KLW1 is complementary to KT1, the QTL on chromosome 5A of Nanda2419 for thicker and heavier kernels, in producing larger kernels with higher commercial value, augmenting its usefulness in wheat breeding.

TaSPL14-7A is a conserved regulator controlling plant architecture and yield traits in common wheat (Triticum aestivum L.).

Plant architecture is a crucial influencing factor of wheat yield and adaptation. In this study, we cloned and characterized TaSPL14, a homologous gene of the rice ideal plant architecture gene OsSPL14 in wheat. TaSPL14 homoeologs (TaSPL14-7A, TaSPL14-7B and TaSPL14-7D) exhibited similar expression patterns, and they were all preferentially expressed in stems at the elongation stage and in young spikes. Moreover, the expression level of TaSPL14-7A was higher than that of TaSPL14-7B and TaSPL14-7D. Overexpression of TaSPL14-7A in wheat resulted in significant changes in plant architecture and yield traits, including decreased tiller number and increased kernel size and weight. Three TaSPL14-7A haplotypes were identified in Chinese wheat core collection, and haplotype-based association analysis showed that TaSPL14-7A-Hap1/2 were significantly correlated with fewer tillers, larger kernels and higher kernel weights in modern cultivars. The haplotype effect resulted from a difference in TaSPL14-7A expression levels among genotypes, with TaSPL14-7A-Hap1/2 leading to higher expression levels than TaSPL14-7A-Hap3. As favorable haplotypes, TaSPL14-7A-Hap1/2 underwent positive selection during global wheat breeding over the last century. Together, the findings of our study provide insight into the function and genetic effects of TaSPL14 and provide a useful molecular marker for wheat breeding.

Diallel analysis of kernel weight and grain‐filling traits in maize grown under contrasting nitrogen supply

AbstractUnderstanding the inheritance of maize (Zea mays L.) kernel weight (KW) under contrasting nitrogen (N) supply is crucial for obtaining high KW across diverse N conditions. This work evaluated broad‐sense heritability (H2), general combining ability (GCA), and specific combining ability (SCA) under contrasting N levels for (i) KW and kernel number per plant and (ii) grain‐filling traits represented by the duration of lag and effective filling phases, kernel growth and desiccation rates, maximum water content and volume, and moisture content at physiological maturity. A six‐parent full diallel cross generated via Griffing's method 3 was tested under high (N200) and low (N0) N supply in 2 years (Y). For the various traits: (i) F1 hybrid, and F1 by Y and/or N interactions were significant (p < 0.05); (ii) GCA was significant at both N levels and affected (p < 0.05) by the Y effect; (iii) SCA was important (p < 0.05) only at N200; and (iv) GCA sum of squares was higher than those of SCA (except for KW). For KW and grain‐filling traits, H2 and GCA/SCA ratios were higher at N0 than at N200, suggesting low‐N environments would be more advantageous for developing genetic selection. Lag‐phase duration (LPD), kernel desiccation rate (KDR), and kernel maximum water content (KWCMAX) had higher H2 (≥0.70) and GCA/SCA ratio than KW, particularly under N0. Thus, the highest KW hybrid (LP2×LP662) was composed of inbreds with high GCA for LPD, KDR and KWCMAX, revealing superior KW hybrids could be selected from the GCA of mentioned traits.

Comparative assessment of grain quality in tannin versus non‐tannin sorghums in the sorghum association panel

AbstractBackground and ObjectivesThe presence of antinutritional compounds such as tannins reduce the nutritional benefits in sorghum. Hence, the major objective was to evaluate the differences in grain quality and physical parameters in 254 tannin and non‐tannin accessions in a diverse set of sorghum association panel.FindingsWide variability was noticed for total protein (11%–19%) and protein digestibility (13%–78%). Tannin content recorded a significant negative relationship (R2 = 0.65, p < .001) with protein digestibility, indicating strong impact of tannins on protein digestibility in sorghum accessions with a pigmented testa. Non‐tannin accessions exhibited higher protein content, protein digestibility, kernel hardness, kernel weight and diameter, and lower phenolics compared to tannin accessions. Among the genetic races, Durra had the highest protein digestibility and Caudatum had the highest kernel weight than other races. In accessions with tannin, red grains had the highest tannin content and lowest protein digestibility than other colored grains.ConclusionsThe study revealed accessions with high protein digestibility of around 71% in both non‐tannin and tannin groups. A tannin containing accession SC1056 had the highest protein digestibility (78%) coupled with high kernel hardness.Significance and NoveltyAccessions with above‐average protein digestibility, either with or without tannins could be ideal donors for breeding for improved grain quality in sorghum.

Comparison of Morphometric Traits of Pecan Cultivars

Pecan is a major horticultural nut tree that originated in North America and, in Turkey, it is generally cultivated in the Aegean and Mediterranean regions. In this study, morphometric traits of twenty-one cultivars grown under equal ecological conditions in the Southeastern region of Turkey were determined. In addition, a multivariate analysis was performed on morphometric traits for determining suitable cultivars that show the best performance in these ecological conditions. The nut weight ranged from 3.66 g for ‘Cherokee’ to 10.35 g for the ‘Shoshoni’ cultivar. The ‘Choctaw’ had the highest kernel weight and kernel ratio ranging from 5.63 g to 58.60%. While the ‘Cherokee’ had the lowest ranging from 0.91 g to 22.84 g, respectively. A significant positive correlation between nut weight and kernel ratio was determined. The kernel weight was also highly correlated with nut weight and height. The use of clustering analysis according to Ward’s method allowed the establishment of relationships between pecan cultivars by separating them into four main clusters. Also, these results were supported by principal component analysis, and ‘Big Z’ and ‘Ideal’ cultivars were determined to be the closest cultivars. Results showed that there are quantitative differences regarding the genetic property of pecan cultivars and more than half of the examined cultivars showed a good performance in terms of nut quality criteria that are crucial in marketing. Furthermore, the multivariate analysis was effective in the differentiation of pecan cultivars and it has been evaluated that it can be used successfully in future studies.

Marker-assisted backcross breeding for heat tolerance in bread wheat (Triticum aestivum L.).

Manipulation of flowering time for adaptation through natural or genetic approaches may combat heat-stress damage that occurs at the reproductive stages in production conditions. HD2733, a popular wheat variety of the eastern plains of India, is largely sensitive to heat stress. Therefore, the current study aims to improve heat tolerance of HD2733 by introgression of QTLs associated with early anthesis and high kernel weight linked to markers Xbarc186 and Xgwm190, respectively, through marker-assisted backcross breeding (MABB) from a tolerant donor, WH730. A total of 124 simple sequence repeat (SSR) markers distributed evenly across the genome were used for the background selection. The alleles of Xbarc186 and Xgwm190 were fixed in BC2F1 and BC1F2 generations by selecting individual plants heterozygous for both marker loci and backcrossed with HD2733 and simultaneously selfed to generate BC2F1 and BC1F2 populations, respectively. Furthermore, the selected BC1F2 were selfed to generate the BC1F4 population. By background screening, a total of 39 BC2F3 and 21 BC1F4 families homozygous for the targeted QTLs with 90.9-97.9% and 86.8-88.3% RPG recoveries were selected. The best performing 17 BC2F3 and 10 BC1F4 lines were evaluated for various morpho-physiological traits. Phenotypic evaluation and multi-location trials of the introgressed lines under late sown conditions led to the selection of three promising lines with early anthesis and higher grain yield. The improved lines will serve as an excellent genetic material for functional genomics and expression studies to understand the molecular mechanisms and pathways underlying the stress tolerance.

Comparison of methods for selecting a promising walnut gene pool according to fruit quality

Background. Walnut (Juglans regia L.) is considered a particularly valuable plant for humans. A number of methods have been developed to select the species’ gene pool that produces high-quality fruits. Breeders need to know which of them ensures identification of the best ancestors. The objective of this work was to compare the effectiveness of the most frequently used techniques for selecting a valuable gene pool according to taste, extractability, weight, kernel yield, and overall fruit score. They were presented in the Program and Methods for Walnut Breeding (method 1) and the Program and Methodology of Variety Studies for Fruit, Berry and Nut Crops (method 2).Materials and methods. Statistical data processing was performed using the licensed Stadia-8 software.Results. Comparing the results with the program requirements for new cultivars, all the ancestors selected according to method 1 had better taste and higher kernel weight, while according to method 2 12.5% of the forms showed lower values. The recommended kernel yield of 50% or more turned out to be lower than the threshold value in 14.29% (method 1) and 62.5% (method 2) of the selected ramets. Evaluation by to method 1 showed that the group of the “superior quality” breeding category had higher average values in taste (by 3.63%), weight (7.86%), extractability (4.25%), and kernel yield (9.9%). When selecting the first-rank forms by method 1, the values were higher in extractability (by 0.25%), weight (5.26%), taste (3.09%), kernel yield (7.55%), and overall score (7.61%). In the average values for the first-rank and second-rank forms, the excess was by 4.44, 21.91, 4.75, 9.67, and 9.86%, respectively.Conclusions. When selecting a promising walnut gene pool, method 1 provides for stricter selection and higher food quality indicators (taste, extractability, weight, kernel yield, and overall fruit score) compared to method 2.

Gene Action for Kernel Weight Per Plant in Spring Barley

The breeding and genetic peculiarities for kernel weight per plant in spring barley varieties of different origin (Ukraine, Western European countries, and Canada), purposes of usage (forage, malting, food) and botanical varieties (covered and naked, awned and awnless) under conditions of Ukrainian Forest-Steppe were revealed. In the diallel crossing scheme with only elite malting barley varieties accordance with the additive-dominant system and overdominance in loci were found. The manifestation of kernel weight per plant was reliably increased by the dominant effects. Accordingly to the indicator of the degree of phenotypic dominance, parameters of genetic variation, graphical regression analysis, effects of GCA and constants of SCA in the hybrid populations will be effective final selection for high kernel weight per plant in later generations, when dominant alleles become homozygous. When different botanical varieties were involved in crosses much more complex gene action for the trait manifestation with strong epistasis and multidirectional dominance were determined. Thus, it is theoretically possible to select plants with high productivity on recessive or dominant basis. The negative aspect is that it will require further extensive evaluation of the splitting generations. Awned spring barley varieties Datcha and MIP Myroslav, as well as awnless variety Kozyr can be used as an effective genetic source for involvement in crossings aimed to improving the kernel weight per plant. Naked spring barley varieties require more breeding improvement in plant productivity compare to covered ones.

Kernel weight responses to the photothermal environment in maize dent × flint and flint × flint hybrids

AbstractMaize (Zea mays L.) grain yield is assumed to be source limited during the flowering period but sink limited during grain growth; however, environmental restrictions during active grain filling may strongly affect final kernel weight (KW). In this study, we evaluated the effect of natural changes in photothermal conditions during lag phase (LP) and effective grain‐filling period (EGFP) on KW, its physiological determinants, and the post‐flowering source–sink relationships of flint and semident germplasm. F1 hybrids of flint × flint and dent × flint background were tested during four seasons (Y1, Y2, Y3, and Y4). Across years, the highest KW (286 mg) was obtained under the maximum photothermal quotients during LP (PTQLP = 1.18 MJ m−2 °C−1) and EGFP (PTQEGFP = 1.07 MJ m−2 °C−1) of Y2, whereas the smallest KW (252 mg) and source–sink ratio during grain filling was obtained under the lowest PTQEGFP (.79 MJ m−2 °C−1) of Y3. Supra‐optimum temperatures during LP of Y3 negatively affected potential KW determination, and hence kernel growth rate (P < .001) as a result of reduced assimilate availability per kernel. Hybrids dent × flint exhibited higher grain yield, kernel number, and plant growth around flowering than flint × flint throughout evaluated seasons but had reduced source–sink relationship during grain filling (P < .05) and increased KW sensitivity (P < .001) to changes in the photothermal conditions. Results emphasized the importance of the photothermal environment during grain filling on KW determination (particularly for seasons with great photothermal imbalance between filling subphases) as well as the dependency of KW responses on the genetic background.

Yield determinants, root distribution and soil water uptake in maize (Zea mays) hybrids differing in canopy senescence under post-silking drought.

Delayed canopy senescence or 'stay-green' (SG) trait in maize (Zea mays L.) could improve drought tolerance. Two field trials comparing four to six maize hybrids with different senescence rate were carried out at Buenos Aires, Argentina, varying water availability during the reproductive period. Green leaf area at maturity was related to kernel weight (r2=0.94***) but its relationship with yield was weaker (r2=0.51-53*) and post-silking dry matter remobilisation was negatively related with the SG trait (r2=0.84**). Two additional experiments were carried out in 63 L pots by withholding irrigation in half of the pots after silking. The SG hybrid achieved lower root biomass at silking, a shallower root distribution and larger root growth in the post-silking period. Under drought conditions, stomatal conductance was lower in the SG hybrid but photosynthetic electron transport rate was higher. Higher post-silking dry matter assimilation in the SG hybrid was compensated for by higher dry matter remobilisation in the non-SG. Higher kernel number per plant in the non-SG hybrid with no ability to compensate for by higher kernel weight in the SG, resulted in slightly higher yields in the non-SG under drought. A water conservation strategy associated with a shallower root system could be linked to the SG trait, promoting faster water depletion at upper soil levels and reduced stomatal conductance at the leaf level but with no conclusive yield advantage.

Effects of barley type and processing method on rumen fermentation, dry matter disappearance and fermentation characteristics in batch cultures

The objective of this study was to investigate the effects of barley type (two-row versus six-row) and processing method (grinding, dry-rolling and temper-rolling) on processing quality, dry matter (DM) disappearance (DMD), and fermentation characteristics in batch culture. The study was a completely randomized design with 2 barley types × 3 processing methods in a factorial arrangement. Thirty barley cultivars/lines were selected from a set of 85 cultivars/lines that were previously screened for in vitro DMD. The mean DMD values (g/kg) were 328 (low), 520 (medium), and 688 (high) after 48 of incubation. Ten representative samples of each DMD group (low, medium and high) of two- and six-row barley were selected. Barley samples were ground (1-mm screen), and dry- or temper-rolled to a processing index (PI) of 0.80. Particle size distribution (PSD) of rolled barley across 4.00-, 3.35-, 2.36-, 1.18-, 0.85-mm sieves, gas production (GP) kinetics, DMD and fermentation traits at 6, 24 and 48 h of incubation were measured. Two-row had higher kernel weight, test weight, plumpness, starch and ether extract content, and lower fibre content than six-row barley (P < 0.01).The PSD of rolled barley was affected by barley type, processing and their interaction (P < 0.01). More (P < 0.01) coarse particles were retained on the 3.35-mm sieve for two-row versus six-row barley (dry-rolled, 0.44 versus 0.34; and temper-rolled, 0.91 versus 0.85). Compared to six-row, two-row barley had greater (P < 0.01) DMD after 6 and 48 h and greater (P = 0.02) crude protein disappearance (CPD) after 48 h. Ground barley had higher DMD, CPD, microbial N production and molar proportion of propionate and total VFA production than rolled barley (P < 0.01); whereas these variables did not differ between dry- and temper-rolled barley. A barley type × processing interaction for DMD, CPD and GP kinetics was identified (P < 0.01). Coarse particles were negatively, while fine particle were positively correlated with DMD (P < 0.01). These results indicate that although PSD of dry- and temper-rolled barley differed, impacts on GP and DMD were small, particularly for two-row barley. The differences in DMD at 6 or 48 h between two- and six-row barley suggest that barley type can impact both the rate and extent of barley digestion in the rumen. These differences suggest that there is considerable opportunity to select barley varieties based on responses to processing and ultimately their feed value for ruminants.

TaDA1, a conserved negative regulator of kernel size, has an additive effect with TaGW2 in common wheat (Triticum aestivum L.).

SummaryKernel size is an important trait determining cereal yields. In this study, we cloned and characterized TaDA1, a conserved negative regulator of kernel size in wheat (Triticum aestivum). The overexpression of TaDA1 decreased the size and weight of wheat kernels, while its down‐regulation using RNA interference (RNAi) had the opposite effect. Three TaDA1‐A haplotypes were identified in Chinese wheat core collections, and a haplotype association analysis showed that TaDA1‐A‐HapI was significantly correlated with the production of larger kernels and higher kernel weights in modern Chinese cultivars. The haplotype effect resulted from a difference in TaDA1‐A expression levels between genotypes, with TaDA1‐A‐HapI resulting in lower TaDA1‐A expression levels. This favourable haplotype was found having been positively selected during wheat breeding over the last century. Furthermore, we demonstrated that TaDA1‐A physically interacts with TaGW2‐B. The additive effects of TaDA1‐A and TaGW2‐B on kernel weight were confirmed not only by the phenotypic enhancement arising from the simultaneous down‐regulation of TaDA1 and TaGW2 expression, but also by the combinational haplotype effects estimated from multi‐environment field data from 348 wheat cultivars. A comparative proteome analysis of developing transgenic and wild‐type grains indicated that TaDA1 and TaGW2 are involved in partially overlapping but relatively independent protein regulatory networks. Thus, we have identified an important gene controlling kernel size in wheat and determined its interaction with other genes regulating kernel weight, which could have beneficial applications in wheat breeding.

Joint optimization of irrigation and planting pattern to guarantee seed quality, maximize yield, and save water in hybrid maize seed production

Abstract Severe water scarcity necessitates the development of a scientifically informed basis for efficient crop irrigation. Both irrigation and crop planting pattern (the planting dates and the planting ratio for male to female maize inbred lines) affect the yield components in hybrid maize production. A high kernel weight, which affects seed germination, is critical in maize seed production. Therefore, the aim of this study was to build a system that jointly optimizes irrigation and planting pattern (JOIPP) to guarantee a suitable kernel weight, maximizes yield, and saves water. The JOIPP was based on a model which could simulate flowering, predict kernel number and estimate the upper and lower limits of kernel weight based on the evapotranspiration and planting pattern. Parameters in JOIPP were calibrated and validated using data from experiments conducted from 2014 to 2016 in Hexi Corridor, northwestern China. A weighted sum method was used to maximize yield and minimize irrigation. A genetic algorithm with a modified initial population generation module was used to solve this optimization problem. Results showed that when the minimum lower limit of kernel weight (LowKWmin) increased, there was decreased irrigation at the flowering stage, increased irrigation at the grain-filling stage, less optimal yield and water use efficiency when the available water insufficient. However, the associated risk of seed germination failure decreased. The optimized planting pattern, compared with the crop planting pattern used by local farmers, increased yield by about 10% and water use efficiency by about 7.3% when LowKWmin was 260 mg/kernel. JOIPP is a useful tool that enables farmers and seed companies to save water and improve yield and seed quality when planting and irrigating maize for hybrid seed production.

Influence of grain quality characteristics and basic processing technologies on the mineral and antinutrient contents of iron and zinc biofortified open‐pollinated variety and hybrid‐type pearl millet

SummaryThe present study aimed at determining whether mineral biofortified pearl millets will continue to maintain significantly higher iron and zinc contents after processing, and the effects of decortication, steeping/fermentation and parboiling on mineral, phytate and total phenolic contents in eight varieties of pearl millets (two biofortified hybrids, Dhanashakti and ICMH 1201, five improved varieties with high iron content and one traditional variety) were also investigated. The hybrids showed higher iron and zinc contents after processing compared to the improved varieties, for example, 17–51% and 10–26% higher iron and zinc contents, respectively, after steeping/fermentation followed by decortication compared to the best varieties. Phytate:mineral ratios also indicated that iron bioavailability was higher in the hybrids after processing, several times above the critical 1:1 ratio. Across all the types, iron content after processing was positively correlated (P ≤ 0.05) with high kernel weight, large kernels, and high fat content, and zinc content was positively correlated with high fat content. These kernel characteristics should aid in the selection of high iron and zinc pearl millet types.

Phenological and Morphological Traits of Important Hazelnut Cultivars in North West Bosnia

The paper presents the results of the analysis of phenological and morphological characteristics of 3 hazelnut cultivars present in the production plantation in the north-western Bosnia and Herzegovina. The 'Rimski', 'Istarski dugi' and 'Tonda Gentile Romana' cultivars served as research material. Blooming time ranged from December to March. For all cultivars, the occurrence of dichogamy, precisely protandry, was observed. The longest flowering period of both male and female flowers was found in the 'Tonda Gentile Romana' cultivar. The 'Rimski' cultivar had the highest fruit weight (3.04 g). 'Tonda Gentile Romana' had the highest kernel weight (1.50 g). The highest kernel percentage (49%) was found in 'Istarski dugi'. The length of male catkins ranged from 21.73 cm to 29.76 cm. Statistically significant differences among cultivars were found for the following traits: the length of male catkins, the number of female flowers in glomeruli, and the number of nuts on a fruiting shoot. The 'Istarski' cultivar had the highest average length of male catkins (29.76) and the highest number of female flowers in the glomeruli (7.32). 'Tonda Gentile Romana' had the highest number of fruits (20.93) on the shoots. All three cultivars have proven to be good varieties in terms of phenological and morphological characteristics, so they can be recommended for intensive production of this nut crop.

Morphological, mechanical and antioxidant properties of Portuguese almond cultivars.

The aim of this study was to evaluate morphological (of fruit and kernel), mechanical (namely shell rupture force) and antioxidant properties (including phenolics and flavonoid content) of five Portuguese almond cultivars, comparing them with two commercial cultivars (Glorieta and Ferragnès). Of the analyzed traits, nut and kernel dimensions varied substantially and were used to describe cultivars. However, some traditional cultivars recorded similar (Pegarinhos), or even higher (Amendoão, Casanova and Refêgo) nut and kernel weight than commercial cultivars. Furthermore, shelling percentage of traditional cultivar (Bonita) was higher than commercial cultivars. Rupture force necessary to break fruits of all traditional cultivars was higher than commercial ones, and was correlated to nut weight cultivars. The phenolics, flavonoids content and antioxidants were higher for Casanova. Parameters like high kernel weight, low percentages of double kernels or losses during shelling and considerable higher phenolics and flavonoids content may be considered by industry during selection of almond.

The effect of irrigation level in the kernel dry matter accumulation period on almond yield, kernel dry weight, fruit count, and canopy size

The effect of irrigation regime in the kernel filling stage of almond was examined in a field experiment. The experiment was conducted on 9-year-old local variety (Um-El-Fahem) grafted on GF677 rootstock in Israel. Five irrigation treatments were applied during the main kernel dry matter accumulation. Irrigation rates in June varied from ~1 to ~8 mm/day and midday stem water potentials varied from ~−2.6 to ~−1.3 MPa. Seasonal irrigation varied from 394 to 801 mm. Kernel yield increased in the high irrigation treatments in the first four seasons where it decreased in the three lower irrigation treatments. Similarly, the four-season trunk cross-sectional area accumulation increased with increasing irrigation. Kernel yield increased with both midday stem water potential and irrigation rate. Kernel dry weight decreased with increasing fruit count where higher kernel weights were found in the higher irrigation treatments at similar fruit count. Kernel relative growth rates of all treatments were similar along the dry matter accumulation stage except for around 1 June where the lowest irrigation rate had significantly lower growth rate. Spurs survival analysis showed that the number of fruits per spur, fruiting spurs, and alive spurs increased with increasing irrigation.

Spraying exogenous 6-benzyladenine and brassinolide at tasseling increases maize yield by enhancing source and sink capacity

The endosperm contributes approximately 80% of the final kernel weight in maize. Plant hormones that affect cell proliferation might increase endosperm cells and establish greater kernel sink capacity, which would improve grain yield. In this study, 6-benzyladenine (BA) and brassinolide (BR) were separately sprayed at tasseling to regulate kernel endosperm cell division, and EDAH (a mixture of ethephon and diethyl aminoethyl hexanoate) was foliar applied at the jointing stage to enhance lodging resistance. The results showed that the two hormones sprayed at tasseling could hamper leaf senescence, improve photosynthesis and significantly increase the number of kernel endosperm cells by 6.2-40.4%, resulting in a high grain filling rate and high kernel weight. Additionally, the tasseling treatments increased grain yield by 2.9-16.0% in both years. There were no significant differences between EDAH and control conditions in sink capacity and yield. The correlation analysis suggested that grain weight and yield had a close correlation with the number of endosperm cells and the filling rate in the lag stage. We concluded that the lag stage played a vital role in constructing sink capacity, and treating maize with BA or BR at tasseling can apparently increase the source and sink capacity to improve the grain filling rate and yield.

AAC Jatharia Canada Western Red Spring wheat

AAC Jatharia (BW483) is a hollow-stemmed, high-protein, and high-yielding spring wheat (Triticum aestivum L.) for the longer growing season areas of the Canadian Prairies. AAC Jatharia was the highest yielding line in the Central Bread Wheat Cooperative (CBWC) Registration Tests performed in the eastern prairies in 2011, 2012, and 2013. Over 2 yr of testing (2011–2012), AAC Jatharia had grain yield 2.5% higher than Unity, 11.6% higher than 5603HR, 7.8% higher than McKenzie, and 19.2% higher than CDC Teal across all locations. In 2013, AAC Jatharia yielded 6.3% higher than Unity across all Manitoba and Saskatchewan locations. AAC Jatharia was resistant to leaf rust (Puccinia triticina Erikss.), and had intermediate resistance to stem rust (Puccinia graminis f. sp. tritici), stripe rust (Puccinia striiformis Westend), leaf spot complex, and Fusarium head blight (FHB) (Fusarium graminearum) infection, with lower FHB index and deoxynivalenol (DON) content compared with Unity. AAC Jatharia was resistant to infestation of the orange wheat blossom midge (Sitodiplosis mosellana Géhin) evaluated over 2 yr (2012 and 2013). It had higher kernel weight and test weight compared with all check cultivars, whereas its maturity was within the range of the check cultivars. AAC Jatharia is registered in the Canada Western Red Spring Wheat class for its premium quality attributes.