Abstract
The increased unpredictability in amount and timing of rain, spells of heat and drought has affected grain yield and threatened food security worldwide. Therefore, untapped genetic resources are needed to be exploited for future gain in yield potential under heat and other stress types. Herein, a panel of 44 wheat landraces stored in gene bank was characterized for yield potential, heat tolerance and resistance against yellow rust (YR) and leaf rust (LR) during three consecutive years. Based on principal component analysis, local Pakistani landraces were identified as potential genetic resources with wide extent of variation in all agronomic, heat tolerance traits and YR, LR score. The TGW had positive correlation with spikelets per spike (Sp/S), spike length (SL), yield, normalized difference vegetation index (NDVI) and canopy temperature depression (CTD). The heat tolerance measure NDVI (A) and CTD (B, A) were significantly correlated with grain yield in positive direction for all the three years. For YR disease prevalence was of eight categories from 0 to TS. The 0 reaction of YR and LR was observed on 69.4% and 3.5% landraces, respectively. The three prominent heat tolerant landraces were C-250, T16 and Local White that can be used as genetic resources for tackling increasing heat stress as a result of climate change through introgression of heat tolerance trait into high yielding wheat cultivars. Furthermore, the tolerant and susceptible landraces can be crossed to produce genetic populations such as recombinant inbred line (RILs) and near isogenic lines (NILs) to identify quantitative traits loci (QTL5)/genes underpinning heat tolerance. (C) 2019 Friends Science Publishers