DEVELOPMENTAL GENETIC ANALYSIS FOR CRUDE FIBER CONTENT AND CRUDE ASH CONTENT OF RAPESEED MEAL IN TWO DIFFERENT GROWING YEARS

Abstract

Developmental genetic analyses method for diploid seed quantitative traits was used to determine the unconditional and conditional genetic main effects and genotype × environment interaction effects from embryo, cytoplasm and maternal genetic systems on crude fiber content (CFC) and crude ash content (CAC) of rapeseed meal in two growing years. The results suggested that the performance at most developmental times/stages for CFC and CAC was mainly affected by the genetic main effects. By using the conditional analysis method, for the different genetic systems, CFC and CAC were simultaneously controlled by the genetic effects from three genetic systems, especially for the maternal main effects. Also, the additive effects were more prominent at most developmental times/stages, and the improvement of both traits could be expected in earlier generation(s) in rapeseed breeding programs. The heritability analysis revealed that the maternal heritability was more prominent during seed development times, especially at maturity. Thus, it suggested that maternal plant selection could be utilized to reduce CFC and increase CAC in rapeseed meal breeding programs. The study further suggested Youcai 601 could be used for reducing CFC, while Huashuang 3 and Zhongyou 821 were suitable for increasing CAC in rapeseed, as evidenced from their predicted parent effects. PRACTICAL APPLICATIONS Rapeseed is an industrially and commercially important oilseed crop. For the oilseed industry, the meal remaining after oil extraction represents a product of a value equal to that of the oil itself. It represents a very valuable protein component of feed mixes that are, in turn, indispensable in modern monogastric animals raising for intensive production of meat, eggs and milk. In certain cases, the oilmeal is further processed to produce concentrates (with 50–60% of crude protein) or isolates (nearly pure protein) for use in human food. Rapeseed flours, protein concentrates and isolates are lower in protein but higher in crude fiber and ash contents than corresponding soybean products. Also, rapeseed or canola meal has been used as fermentation substrate, as an additive in compost for commercial button mushroom (Agaricus bisporus) production and also as substrate for xylanase production by Trichoderma reesei. Oilmeals are mainly valued for low fiber content, high protein content of good quality and absence or low presence of toxic and antinutritional compounds. One drawback of rapeseed meal is its higher crude fiber content, which results in lower digestible energy, especially for non-ruminants. Decreasing the crude fiber and improving the crude ash (an indicator of the mineral content) could increase the demand for rapeseed meal as a feed source for livestock.