Potential of the C Genome of Different Variants of Brassica oleracea for the Improvement of Agronomic and Seed Quality Traits of B. napus Canola

Abstract

ABSTRACTThe narrow genetic base of Brassica napus L. canola, especially of its C genome, is an impediment for continued improvement of this crop. We investigated the gene pools of different variants of B. oleracea L. to improve agronomic and seed quality traits of B. napus canola. For this, B. napus canola inbred populations were developed from six interspecific crosses, involving a single B. napus canola line and six accessions of B. oleracea belonging to four variants of this species, following two breeding techniques (F2– and BC1–derived lines). Among these, the population derived from crossing with var. italica gave the greatest seed yield and also had shorter duration of flowering than most of the other populations. The population developed using var. botrytis had the highest seed oil content, and seed yield was comparable with the population developed using var. italica. Populations based on var. capitata had the lowest oil but greater protein content than most of the populations. Several lines from these interspecific crosses exceeded seed yield of the B. napus parent and also had acceptable agronomic and seed quality traits. Comparing the two breeding techniques, the F2–derived population gave greater yield than the BC1–derived population, whereas the BC1–derived population flowered and matured earlier than the F2–derived population. Genetic distance of the inbred lines from the B. napus parent showed positive correlation of r ≥ 0.4 with days to flowering and seed protein content and negative correlation with seed oil content, whereas correlation with seed yield was negative and weak (r = −0.18). Thus, the results showed that the B. oleracea gene pool, especially var. italica and botrytis, can be used to improve spring B. napus canola, as well as to broaden the genetic base of this crop.