Pea Phenology: Crop Potential in a Warming Environment

Abstract

One hundred and seven recombinant inbred lines (RILs) were developed from the cross of field pea ( Pisum sativum L.) cultivars CDC Centennial × CDC Sage with the objectives of evaluating phenology and yield components, and to map the quantitative trait loci (QTLs) responsible for these traits. Experiments were conducted in 2013 using normal seeding date at Saskatoon and Rosthern in Saskatchewan, and in 2014 using both normal and late seeding. The late seeding date was used to expose the plots to a more heat stressful environment, analogous to that experienced in warmer regions of the North American prairies. Days to flowering termination (DTFT) was positively correlated with final seed yield under both normal and late seeding conditions. Among the yield components, pod number (PN) was most positively associated with seed yield, followed by thousand seed weight (TSW) and seed number per pod (SNPP). A genetic linkage map consisting of 1024 loci with a total coverage of 1702 cM was developed using SNP markers. Ten QTLs were found consistent over more than one environment, five for flowering traits and five for yield component traits. A stable QTL at Linkage Group 6b for days to flowering was detected over four environments. The QTLs for flowering duration, TSW and reproductive node number were different between normal and late seeding, which implies different mechanisms were involved under the contrasting environments.