Pleiotropic QTLs affecting heading date/flowering time and quality traits in durum wheat

RONCALLO PABLO F.; ECHENIQUE VIVIANA C.

Colonia

Seminario; Seminario Internacional: 1914-2014, Un siglo de mejoramiento de trigo en La Estanzuela; 2014

INIA Uruguay La Estanzuela

The QTL analyses are a powerful tool to dissect complex phenotypic traits. We conducted a study to map QTLs associated with heading date and flowering time by using a durum wheat RIL population obtained from the cross between the UC1113 line and the Kofa variety. This population was previously used to report QTLs for quality traits (grain color, carotenoids content , protein content and gluten strength).We perform new analyses by using heading date and flowering time data sets and were localized pleiotropic QTLs in three genomic regions associated with heading date/flowering time and quality. In particular, 1) on chromosome arm 2BS (Xwmc154 -Xcnl158) associated with brightness (L*value) and protein content, 2) on 3BS (Xcfd79 - Xksm45) affecting flour redness (a* value), gluten strength; and 3) on 7BL (Xcfa 2040 - Xbarc1073) with effect on flour yellow color (b* value), carotenoid pigment content and protein content. One additional region on chromosome arm 6AL (Xbarc113 - Xwmc553) was affecting heading date, flour redness (a* value), gluten strength and it was a strong QTL for carotenoid pigment content and flour yellow color (b* value). The 6AL QTL was one of the two QTL mapped on average data of heading date (5 environments), explaining 20.8% of variation, and behind the main mapped QTL for heading date on 2BS (putative position of Ppd-B1). The QTL on 7BL was mapped by using flowering time average data (5 environments) and surprisingly corresponds with the second QTL in order of importance for both protein content, carotenoids pigment and flour yellow color in this population. This region explained from 11 to up to 23% of the variance in flowering time and 18.2% of heading date in one environment. In both, 6AL and 7BL QTLs, the Kofa allele increases the days from sowing to heading/flowering and an improvement of quality parameters involved, indicating that a delay in the heading/flowering was associated with increased protein and carotenoid content,  a better gluten and color in these regions. However, for the 2BS and 3BS QTLs, the quality has improved in the RILs carrying the opposite allele which causes the heading date (or flowering time) will be delayed.