Mapping of quantitative trait loci for resistance to race 1 of Pyrenophora tritici‐repentis in synthetic hexaploid wheat

Tan spot, caused by a necrotrophic fungus Pyrenophora tritici‐repentis (Ptr), has become an important foliar disease of wheat worldwide. Effective control of tan spot can be achieved by deployment of resistant wheat cultivars. An F_2:3 population derived from a cross between synthetic hexaploid wheat (SHW), TA4161‐L1 (moderately resistant) and susceptible winter wheat cultivar, ‘TAM105’ was evaluated with race 1 of Ptr under controlled conditions. The population was genotyped using Diversity Arrays Technology (DArT). Presence of transgressive segregants indicated contribution of positive alleles from both parents. Two major QTLs were located on the short arm of chromosomes 1A and 6A and designated as QTs.ksu‐1A and QTs.ksu‐6A, respectively. Two additional QTLs were identified on chromosome 7A. Resistant alleles of all the QTLs were contributed by TA4161‐L1. Novel QTLs on 6A and 7A can be a valuable addition to known resistance genes and utilized in breeding programmes to produce highly resistant cultivars.     

Genetic variation for tolerance to post-emergence herbicide,imazethapyr in lentil (Lens culinaris Medik.)

Weeds pose a serious constraint to lentil production. Identification and deployment of post-emergence herbicide tolerance in improved varieties can help reduce the production cost and increase the productivity and area under lentil cultivation. Imazethapyr, a post-emergence herbicide was tested on 180 lentil genotypes for two consecutive years. Significant variation among the genotypes was observed for tolerance to imazethapyr. On a 1–5 scale, 12 genotypes were found tolerant, 46 moderately tolerant, 112 sensitive and 10 highly sensitive during the first season, and 11 genotypes were found tolerant, 51 moderately tolerant, 110 sensitive and 8 highly sensitive during the second season. Based on the first year’s result, 30 genotypes, representing tolerant, moderately tolerant, sensitive and highly sensitive reactions, were evaluated to determine the effect of herbicide on morpho-physiological and yield traits. The adverse effect of imazethapyr was significant on growth and yield attributes of lentils. Five genotypes namely LL699, LL1397, IPL406, EC78452 and LL1203 demonstrated tolerance to imazethapyr with limited phytotoxic effect on various morpho-physiological traits. These genotypes showed less reduction (<19%) for seed yield in imazethapyr treated plots as compared to control. These genotypes offer scope for developing post-emergence herbicide tolerant cultivars in lentil.