Characterization of a pea recombinant inbred population for resistance to heat at flowering
Date
2016-03-22
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Degree Level
Masters
Abstract
Field pea (Pisum sativum L.) as a cool season legume crop is sensitive to high day time temperature, especially during flowering. A population of 107 recombinant inbred lines (RILs) known as PR-11 was made from the cross of CDC Centennial (heat tolerant cultivar) X CDC Sage (heat sensitive cultivar) with the objectives of screening heat tolerant traits during flowering and subsequent seed development, and to map the quantitative trait loci (QTLs) responsible for these traits. Experiments were carried out in 2012-2014. PR-11 was seeded at normal seeding dates in 2012 and 2013 at Saskatoon (52º12’N, 106º63’W) and Rosthern (52º66’N, 106º33’W) in Canada, and in 2014 PR-11 was seeded at both normal and late seeding (three weeks later than normal) dates at one location, Saskatoon.
Correlation analyses demonstrated that the duration of flowering (DOF) was positively associated with final seed yield under both normal and late seeding date conditions. Yield component traits on the main-stem [reproductive node number (Rnode), pod number (Pod), seed number per pod (Seed), single seed weight (SSW)] were significantly associated with main-stem seed yield, among which pod number appeared to be the component most positively associated with seed yield. However, yield on the main-stem was not significantly associated with seed yield at the plot level, which inferred that the contribution of seed yield on side branches was important.
A genetic map consisting of 369 SNPs markers with a total coverage of 746 cM was developed using JoinMap 4.0. A total of 14 QTLs were detected under environments with normal seeding date, six for flowering traits, and eight for yield component traits. Eight QTLs were identified at late seeding, four for flowering traits and four for yield component traits. The total variation in days to flowering (DTF), DOF, Pod, Seed, SSW and grain yield that were each explained by the QTLs under normal seeding environments was 24 %, 43%, 15%, 32%, 34% and 21%, respectively. The QTLs together accounted for 43% of DTF variation, 14% of DOF variation, 17% of Pod variation, 12% of SSW variation and 12% of grain yield variation at the late seeding date.
Lines PR-11-2, PR-11-88 and PR-11-91 performed as the top yielding lines under both normal and late seeding environments, and could be considered as heat tolerant lines.
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Keywords
Field pea, RILs, QTLs, Flowering and yield traits
Citation
Degree
Master of Science (M.Sc.)
Department
Agricultural and Bioresource Engineering
Program
Plant Science