Assessment of ICCV 2 × JG 62 chickpea progenies shows sensitivity of reproduction to salt stress and reveals QTL for seed yield and yield components

Abstract

Salinity is a complex abiotic stress and understanding the physiological and genetic basis of salinity tolerance is a prerequisite for improving existing crop cultivars. Experiments were undertaken using 126 recombinant inbred lines from a cross between JG 62 (tolerant) and ICCV 2 (sensitive) to characterize traits related to seed yield differences under saline conditions and to map quantitative trait loci (QTL). The population segregated for flowering time and entries were separated into 'early' and 'late' phenology groups to undertake the analysis. In both groups seed yield varied under salinity, with 4 seed number being the most closely related trait to yield. In contrast, seed yield was not related to 100-seed weight or flowering time. Shoot dry weight was positively correlated with seed yield in the early entries only, but had no significant relationship with seed number. The higher sensitivity to salinity of the early entries was related both to a smaller biomass and lesser seed number under saline conditions. A QTL for seed yield under saline conditions was found in linkage group 3 in the late group, and a cluster of QTLs for seed yield components in linkage group 6, including a QTL for seed number which explained 37% of the variation. In contrast, no QTL for seed yield was found in the early group, but a QTL for seed number under saline conditions was found. These data indicate that salinity tolerance traits are linked to the degree of earliness in chickpea. Tolerance is determined by the success of reproductive sites in both early and late entries, which relates in part to constitutive traits, and by the capacity of maintaining growth in earlyflowering lines only. This is the first report of QTLs for seed yield and seed number in chickpea exposed to salinity.

The Chickpea Early Flowering 1 (Efl1) Locus Is an Ortholog of Arabidopsis ELF3

“…A number of QTLs within these regions have been reported previously, including the QTLs on Ca4 (Cobos et al, 2007;Varshney et al, 2014) and Ca5 (Cho et al, 2002;Vadez et al, 2012;Jamalabadi et al, 2013;Pushpavalli et al, 2015). GI remains a potential candidate for qdf-SD4, with markers for CDC Frontier and ICCV 96029 alleles showing a strong association with flowering time under SD (Supplemental Fig.…”

“…Efl1 has been associated previously with several QTLs on Ca3 (Cho et al, 2002;Jamalabadi et al, 2013), Ca4 (Upadhyaya et al, 2015), and Ca5 (Vadez et al, 2012;Pushpavalli et al, 2015). Changes to the naming convention and a lack of common markers between maps are likely to account for some of the reports of Efl1 on different chromosomes.…”

“…Currently, only four loci controlling the crucial trait of flowering time (Efl1-Efl4) have been identified in domesticated chickpea germplasm, and the genes responsible for these loci are unknown. Efl1, the first major flowering time locus described in chickpea, was initially defined in ICCV 2 (Kumar and van Rheenen, 2000), which has been used as a common parent in several crosses that report major QTLs on Ca5, suggesting a likely map position for Efl1 (Cho et al, 2002;Vadez et al, 2012;Jamalabadi et al, 2013;Pushpavalli et al, 2015). Allelism tests have provided strong genetic evidence that this earlyflowering efl1 gene also is present in ICCV 96029, a direct descendent of ICCV 2 .…”

“…In addition, six quantitative trait loci (QTLs) have been reported from chickpea linkage studies (Weller and Ortega, 2015). Several of these studies have involved ICCV 2, which is known to carry efl1, and each of these reported a major QTL on what is now known to be Ca5 (Cho et al, 2002;Vadez et al, 2012;Jamalabadi et al, 2013;Pushpavalli et al, 2015), while Efl2 has been shown to be associated with a QTL on Ca1 (Lichtenzveig et al, 2006). A recent genome-wide association study identified five further flowering time QTLs and put forward eight candidate genes for these QTLs, including an ortholog of the Arabidopsis gene PHOTOPERIOD-INDEPENDENT EARLY FLOWERING1 (PIE1) on Ca4 that is proposed to be synonymous with the Efl1 locus (Upadhyaya et al, 2015).…”

Advances in Chickpea Genomics

“…Several other intra-specifi c mapping populations have been developed and used to identify the markers associated with traits like resistance to fusarium wilt (Tekeoglu et al 2002 ;Udupa and Baum 2003 ;Sharma et al 2004Sharma et al , 2005, resistance to ascochyta blight (Iruela et al 2007 ;Anbessa et al 2009 ;Kottapalli et al 2009 ), resistance to rust (Madrid et al 2008 ), resistance to botrytis grey mold (Anuradha et al 2011 ), salinity tolerance (Vadez et al 2012 ), drought tolerance (unpublished data with ICRISAT), seed traits (Cobos et al 2009 ) and, for grain yield (Rehman et al 2012 ). Several of these studies have been summarized in earlier reviews (Gaur et al 2012 b;Upadhyaya et al 2011 ;Varshney et al 2007 ).…”