Molecular investigations on grain filling rate under terminal heat stress in bread wheat (Triticum aestivum L.)

Grain yield under post anthesis high temperature stress is largely influenced by grain filling rate (GFR). To investigate molecular basis of this trait, a set of 111 recombinant inbred lines (RILs) derived from Raj 4014, a heat sensitive genotype and WH 730, heat tolerant cultivar was phenotyped during 2009-2010 and 2010-2011 crop seasons, under field conditions. The difference in GFR (dGFR) between the timely and late sown conditions was used as a phenotypic parameter to find association with molecular markers, as parental lines exhibited significant difference for this trait. The mapping population showed clear-cut segregation pattern for differences in GFR between timely and late sown conditions. About 75% of the progenies showed no difference while 25% showed significant difference in GFR under high temperature stress created by late sown condition. To study the association of this trait with the markers, the parental lines were screened with 300 simple sequence repeat (SSR) microsatellite markers out of which 15% (45) were polymorphic between parental lines. These polymorphic markers were utilized for genotyping a subset, comprising of 43 RILs that had clear contrasting variation for dGFR. Regression analysis revealed significant association of dGFR of RILs with two markers viz., Xbarc04 and Xgwm314 with coefficients of determination (R2) values of 0.10 and 0.06, respectively.Keywords: Grain filling rate (GFR), simple sequence repeat (SSR), heat tolerance, wheatAfrican Journal of Biotechnology Vol. 12(28), pp. 4439-444

Identification of wheat cultivars for low nitrogen tolerance using multivariable screening approaches

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). A set of thirty-six wheat cultivars were grown for two consecutive years under low and high nitrogen conditions. The interactions of cultivars with different environmental factors were shown to be highly significant for most of the studied traits, suggesting the presence of wider genetic variability which may be utilized for the genetic improvement of desired trait(s). Three cultivars, i.e., RAJ 4037, DBW 39 and GW 322, were selected based on three selection indices, i.e., tolerance index (TOL), stress susceptibility index (SSI), and yield stability index (YSI), while two cultivars, HD 2967 and MACS 6478, were selected based on all four selection indices which were common in both of the study years. According to Kendall’s concordance coefficient, the consistency of geometric mean productivity (GMP) was found to be highest (0.778), followed by YSI (0.556), SSI (0.472), and TOL (0.200). Due to the high consistency of GMP followed by YSI and SSI, the three selection indices could be utilized as a selection tool in the identification of high-yielding genotypes under low nitrogen conditions. The GMP and YSI selection indices had a positive and significant correlation with grain yield, whereas TOL and SSI exhibited a significant but negative correlation with grain yield under both high and low nitrogen conditions in both years. The common tolerant genotypes identified through different selection indices could be utilized as potential donors in active breeding programs to incorporate the low nitrogen tolerant genes to develop high-yielding wheat varieties for low nitrogen conditions. The study also helps in understanding the physiological basis of tolerance in high-yielding wheat genotypes under low nitrogen conditions

Novel sources of variation in grain yield, components and mineral traits identified in wheat amphidiploids derived from thinopyrum bessarabicum (Savul. & rayss) Á. löve (poaceae) under saline soils in India

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. Salt-affected soils constrain wheat production globally. A wild wheat species, Thinopyrum bessarabicum (Savul. & Rayss) Á. Löve (Poaceae), and its derivatives are tolerant of high external NaCl concentrations but have not been tested yet in field conditions. The aim of this study was to study the performance of amphidiploids derived from T. bessarabicum for grain yield (GYD), yield components and grain mineral composition traits under normal and saline soil conditions. Field experiments were conducted at Karnal (pH(water) = 7.3) and Hisar (pH(water) = 8.3) sites in 2014–2015 and 2015–2016 in India. Grain samples were analysed using inductively coupled plasma–mass spectrometry (ICP-MS). Yield and yield component traits of amphidiploids were typically greater at Karnal than Hisar. The GYD was greater at Karnal (1.6 t ha−1) than Hisar (1.2 t ha−1) in 2014–2015. However, GYD was greater at Hisar (1.7 t ha−1) than Karnal (1.1 t ha−1) in 2015–2016. Mean grain zinc (Zn) concentration of eight amphidiploids, averaged across sites and years, varied from 36 to 43 mg kg−1. Some amphidiploids derived from T. bessarabicum showed greater GYD and grain Zn concentration under saline soils (Hisar) than normal soils (Karnal). These might be potential new sources for the development of salt-tolerant wheat varieties with increased grain Zn concentration under salt-affected soils

A putative heat-responsive transcription factor (TaHD97) and its targets in wheat (Triticum aestivum) providing thermotolerance

214-223Transcription factors (TFs) are protein, which perform their role at transcriptional level by affecting the expression of various genes associated with metabolic pathways, growth and stress-associated genes (SAGs) at different developmental stages. Here, we identified 38 novel heat-responsive transcription factor genes from wheat cv. HD2985 by mining the de novo transcriptome data derived from heat shock (HS) treated wheat. Based on digital gene expression (DGE), a putative transcript (TaHD97) of ~1.1 kbas amplified and cloned from wheat cv. HD2985. The presence of heat stress transcription factor (HSF) DNA binding domain was observed in the amino acid sequence. Differential expression of TaHD97 was observed in HD2985 (thermotolerant) and HD2329 (thermosensitive) under heat stress. Tissue specific expression analysis showed up-regulation of TaHD97 in leaves, stem and endospermic tissues and down-regulation in root under HS. A positive correlation was established between the expression of TaHD97 and its target gene (HSP17 and HSP90) in wheat under heat stress. HSP17 transcripts were observed more in leaves of HD2985, as compared to HD2329. Thermotolerance related biochemical enzymes (SOD, CAT, GPX and TBARS) were observed higher in wheat cv. HD2985 showing maximum expression of TaHD97 under heat stress. There is a need for the functional validation of the gene TaHD97 in order to use it for the regulation of sHSP (catalytic chaperone) - a novel approach towards augmenting thermotolerance in wheat under heat stress

Natural resource enhancement through silvipastoral establishment in western Himalayan region

Livestock rearing is an integral part of rural livelihood in the Himalayan region. In spite of abundance of pasture resources, total biomass is insufficient to meet the forage demand. Indiscriminate grazing has caused an alarming decline in the carrying capacity of grazing lands and has caused severe land degradation. This study was carried out with the objective of increasing biomass potential, improving livestock productivity and to arrest environmental degradation. The study was conducted at Ghanetta and Dagoh (Kangra) and Jogindernagar (Mandi) districts in Himachal Pradesh through silvipastoral intervention in conjunction with soil and water conservation measures. Grasslands of the study area were of alluvial–loamy soil with shallow depths. Soil organic matter was 0.72 (Ghanetta), 0.76 (Dagoh) and 0.80% (Jogindernagar). Organic carbon content in the subsurface (15–45 cm) layer was only 30 to 39% of the surface layer (0–15 cm). Chrysopogon (20%) was found the most dominant species, followed by Heteropogon (13%). Average herbage production was 5.613 DM tonne/ha (Ghanetta), 5.458 DM tonne/ha (Dagoh) and 5.233 DM tonne/ha (Jogindernagar). Leaf biomass of different fodder trees ranged from 0.23–0.60 DM tonne/ha (Ghanetta), 0.16–0.51 DM tonne/ha (Dagoh) and 0.21–0.59 DM tonne/ha (Jogindernagar). Maximum biomass of 9.17 DM tonne/ha was obtained at Ghanetta followed by 8.26 DM tonne/ha and 8.23 DM tonne/ha at Dagoh and Jogindernagar, respectively, showing substantial improvement in total biomass potential with silvipastoral intervention in conjunction with soil and water conservation measures

Impact of participatory silvipastoral intervention and soil conservation measures for forage resource enhancement in western Himalaya

Livestock rearing is an important component of rural economy in mid-hills of Himalaya. Inspite of abundant available feed resources, total available biomass is insufficient to sustain the livestock population. Fodder trees particularly in hill ecosystem play an important role in supplementing the fodder requirement especially during the lean period. Information gathered and analysis concludes that Grewia optiva is the most important fodder tree in terms of dominance, palatability and increase in milk yield followed by Artocarpus chaplasha, Morus alba, Bauhinia variegata, Albizia lebbeck and Terminalia alata in Kangra and Mandi districts of Himachal Pradesh. The crude protein content was found highest in Grewia optiva (19.38%) followed by Albizia lebbeck (18.85%), Dendrocalamus hamiltonii (18.01%) and minimum in case of Quercus incana (9.27%). During scarcity of fodder Ficus religiosa is the only fodder tree fed throughout the year. The established silvipasture produced leaf biomass of 2.77 to 6.77 DM kg/tree (Ghanetta), 2.12 to 5.96 DM kg/tree (Jogindernagar) and 2.25 to 6.93 DM kg/tree (Dagoh). Fodder trees planted under silvipastoral system produced average biomass of 1.83 DM tonnes/ha (Ghanetta), 1.49 DM tonnes/ha (Jogindernagar) and 1.66 DM tonnes/ha (Dagoh). Rainfall events of more than 50 mm, though quite less in number (25/165, 24/192 and 17/149), contributed 47.7, 82.3 and 81.7% to the total runoff at Ghanetta, Jogindernagar and Dagoh, respectively. Among the resource conservation measures trenching in combination with vegetative barrier allowed only 8.2% of rain as runoff compared to 41.5% under control (no measure). The silvipasture systems coupled with contour staggered trenches and / or vegetative barrier can effectively arrest the environmental degradation

Variation in grain Zn concentration, and the grain ionome, in field-grown Indian wheat

Wheat is an important dietary source of zinc (Zn) and other mineral elements in many countries. Dietary Zn deficiency is widespread, especially in developing countries, and breeding (genetic biofortification) through the HarvestPlus programme has recently started to deliver new wheat varieties to help alleviate this problem in South Asia. To better understand the potential of wheat to alleviate dietary Zn deficiency, this study aimed to characterise the baseline effects of genotype (G), site (E), and genotype by site interactions (GxE) on grain Zn concentration under a wide range of soil conditions in India. Field experiments were conducted on a diverse panel of 36 Indian-adapted wheat genotypes, grown on a range of soil types (pH range 4.5–9.5), in 2013–14 (five sites) and 2014–15 (six sites). Grain samples were analysed using inductively coupled plasma-mass spectrometry (ICP-MS). The mean grain Zn concentration of the genotypes ranged from 24.9–34.8 mg kg-1, averaged across site and year. Genotype and site effects were associated with 10% and 6% of the overall variation in grain Zn concentration, respectively. Whilst G x E interaction effects were evident across the panel, some genotypes had consistent rankings between sites and years. Grain Zn concentration correlated positively with grain concentrations of iron (Fe), sulphur (S), and eight other elements, but did not correlate negatively with grain yield, i.e. no yield dilution was observed. Despite a relatively small contribution of genotype to the overall variation in grain Zn concentration, due to experiments being conducted across many contrasting sites and two years, our data are consistent with reports that biofortifying wheat through breeding is likely to be effective at scale given that some genotypes performed consistently across diverse soil types. Notably, all soils in this study were probably Zn deficient and interactions between wheat genotypes and soil Zn availability/management (e.g. the use of Zn-containing fertilisers) need to be better-understood to improve Zn supply in food systems

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Dataset of phenotyping recombinant inbred lines population of wheat under heat stress conditions

Heat stress is a genetically complex and physiologically diverse phenomenon. To overcome the effect of heat stress identification of genomic locations associated with heat stress tolerance is essential. This article provides the dataset of phenotyping used in the research article entitled “Mapping QTLs for grain yield components in wheat under heat stress”. The presented data included the phenotyping of the 249 RIL population of F8 and F9 generations under timely and late sown conditions during the 2013-14 and 2014-15 crop seasons, respectively. The RIL population was derived from the cross between HUW510 and HD2808 wheat genotypes. A total of eight agronomic traits were subjected to phenotype and the heat susceptibility index (HSI) of these traits was estimated to identify the effect of heat stress on the parents and RIL population. The presented dataset could be utilized to understand the genetic basis for heat stress tolerance in wheat

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