Stripe rust is a continuous threat to wheat crop all over the world.  It causes considerable yield losses in wheat crop every year.  Continuous deployment of adult plant resistance (APR) genes in newly developing wheat cultivars is the most judicious strategy to combat this disease.  Herein, we dissected the genetics underpinning stripe rust resistance in Pakistani wheat germplasm.  An association panel of 94 spring wheat genotypes was phenotyped for two years to score the infestation of stripe rust on each accession and was scanned with 203 polymorphic SSRs.  Based on D´ measure, linkage disequilibrium (LD) exhibited between loci distant up to 45 cM.  Marker-trait associations (MTAs) were determined using mixed linear model (MLM).  Total 31 quantitative trait loci (QTLs) were observed on all 21 wheat chromosomes.  Twelve QTLs were newly discovered as well as 19 QTLs and 35 previously reported Yr genes were validated in Pakistani wheat germplasm.  The major QTLs were QYr.uaf.2AL and QYr.uaf.3BS (PVE, 11.9%).  Dissection of genes from the newly observed QTLs can provide new APR genes to improve genetic resources for APR resistance in wheat crop.

 

Genetic diversity is the base of any genetic improvement breeding program aimed at stress breeding.  The variability among breeding materials is of primary importance in the achievements of a good crop production.  Herein, 105 wheat genotypes were screened against drought stress using factorial completely randomized design at seedling stage to determine the genetic diversity and traits association conferring drought tolerance.  Analysis of variances revealed that all the studied parameters differed significantly among all genotypes, indicating the significance genetic variability existed among all genotypes for studied indices. The 10 best performance genotypes G1, G6, G11, G16, G21, G26, G39, G44, G51, and G61 were screened as drought tolerant, while five lowest performance genotypes G3, G77, G91, G98, and G105 were screened as drought susceptible.  Root length, chlorophyll a, chlorophyll b, and carotenoid contents were significantly correlated among themselves which exhibited the importance of these indices for rainfed areas in future wheat breeding scheme.  Shoot length exhibited non-significant and negative association with other studied traits, and its selection seems not to be a promising criteria for this germplasm for drought stress.  Best performance genotypes under drought stress conditions will be useful in future wheat breeding program and early selection will be effective for developing high yielding and drought tolerant wheat varieties.