Vaibhav K. Singh

Harnessing genetic potential of wheat germplasm banks through impact-oriented-prebreeding for future food and nutritional security

The value of exotic wheat genetic resources for accelerating grain yield gains is largely unproven and unrealized. We used next-generation sequencing, together with multi-environment phenotyping, to study the contribution of exotic genomes to 984 three-way-cross-derived (exotic/elite1//elite2) pre-breeding lines (PBLs). Genomic characterization of these lines with haplotype map-based and SNP marker approaches revealed exotic specific imprints of 16.1 to 25.1%, which compares to theoretical expectation of 25%. A rare and favorable haplotype (GT) with 0.4% frequency in gene bank identified on chromosome 6D minimized grain yield (GY) loss under heat stress without GY penalty under irrigated conditions. More specifically, the ‘T’ allele of the haplotype GT originated in Aegilops tauschii and was absent in all elite lines used in study. In silico analysis of the SNP showed hits with a candidate gene coding for isoflavone reductase IRL-like protein in Ae. tauschii. Rare haplotypes were also identified on chromosomes 1A, 6A and 2B effective against abiotic/biotic stresses. Results demonstrate positive contributions of exotic germplasm to PBLs derived from crosses of exotics with CIMMYT’s best elite lines. This is a major impact-oriented pre-breeding effort at CIMMYT, resulting in large-scale development of PBLs for deployment in breeding programs addressing food security under climate change scenarios.

Central Wheat Hs562'-A High Yielding Wheat Variety for Timely Sown Production Conditions of Northern Hill Zone

Dharam Pal1*, Madhu Patial1, KV Prabhu2, J Kumar1,7, Santosh Watpade1, RN Yadav3, Sanjay Kumar2, RK Sharma2, GP Singh2,8, Rajbir Yadav2, Vinod2, Anju M Singh2, SV Sai Prasad4, IS Solanki6,9, M Sivasamy5, JB Sharma2, PK Singh2, Neelu Jain2, Niharika Mallik2, Kiran Gaikwad2, Tapas Ranjan Das6, Vikas5, Jaya Prakash5, JB Singh2, Divya Ambati4, Vaibhav Singh2, AN Mishra4, Shivadhar2 and Ajay Arora2 1ICAR-IARI, Regional Station, Shimla, India 2ICAR-Indian Agricultural Research Institute, New Delhi, India 3ICAR-Indian Agricultural Research Institute, Regional Station, Karnal, India 4ICAR-Indian Agricultural Research Institute, Regional Station, Indore, India 5ICAR-Indian Agricultural Research Institute, Regional Station,Wellington, India 6ICAR-Indian Agricultural Research Institute, Regional Station,Pusa, India 7ICAR-NIBSM, Raipur, India 8ICAR-Indian Institute of Wheat and Barley Research, Karnal, India 9ICAR-Krishi Bhawan, New Delhi

Characterization of yellow rust resistance genes by using gene postulation and assessment of adult plant resistance in some Indian wheat genotypes

The yellow rust caused by Puccinia striiformis f.sp. tritici is an important constraint to wheat production worldwide. Host resistance is the most economicalway to manage yellow rust. Race-specific resistance is short-lived and overcome by the evolution of new races of the pathogens. However, non-race-specific, or quantitative resistance, controlled by many genes and effective at the adult plant stage, is generally considered to be more durable and long-lasting. Such type of resistance should be of primary interest to wheat breeders around the world. With this background, old wheat genotypes/cultivars were evaluated against different pathotypes of Puccinia striiformis for resistance at both the seedling and adult plant stages. By applying the gene matching technique, three yellow rust resistance genes viz., Yr2, Yr9 and Yr18 were postulated. Adult plant resistancewas assessed through host response and epidemiological parameters i. e. final rust severity, relative area under rust progress curve, coefficient of infection and infection rate. Promising adult plant resistance was observed on the cultivars DBW 17, DBW 71, PDW 314, HS 507, VL 804, VL 829, VL 907, HPW 251, HPW 349, HD 2967, HD 2985, HD 3043, HD 3086, PBW 660, C 306, HI 1563, WH 1021, WH 1080 and Raj 4083 consistently during rabi seasons of 2013–15. All these promising yellow rust resistant cultivars at adult plant stage were susceptible at seedling stage to one or more pathotype(s) of yellow rust, which indicated the presence of adult plant resistance. At seedling stage, adult plant resistance gene Yr18 was characterized in eight cultivars, namely, HS 277, VL 804, VL 829, HD 2733, NI 5439, NIAW 34, PBW 175 and C 306 where, it occurred in combination with other genes in the seven cultivars. All these wheat cultivars exhibited effective adult plant resistance.

Inheritance of stem rust resistance in Indian bread wheat cultivars

Four Indian bread wheat cultivars viz., DL788-2, GW322, Raj3765 and UP2425 were genetically analyzed against three selected pathotypes 21 (9G5), 40A (62G29) and 117A (36G2) of Puccinia graminis tritici at Indian Agricultural Research Institute, New Delhi. The segregation pattern in seedlings of F2 derived from crosses with Agra Local as susceptible parent showed the presence of three dominant independent genes for stem rust resistance in DL788-2 and Raj 3765, and two dominant independent genes in each GW322 and UP2425 when analyzed with pathotype 21 (9G5). These findings were supported by segregation of F2 seedlings of reciprocal crosses (AL x parent), in same pattern and reconfirmed by analyses of BC1 and BC2 progenies to test pathotypes. The F2 seedlings of all the diallele crosses did not segregate for susceptibility to pathotype 21 (9G5). It indicated that resistance gene(s) may be common in test cultivars, however, some of the diallele crosses showed segregation to pathotypes 40A (62G29) and 117A (36G2) showing dissimilarity of resistance. Genes Sr24in DL788-2, Sr1 1 in GW 322 and Sr31in UP2425 were validated based on pedigree and infection types of cultivars, and confirmed by test of allelism. An adult plant resistance gene Sr2was also identified in all these test cultivars based on mottling effect in the seedlings.