Heterosis for Seed Yield, Oil Content and Other Characters in Rapeseed (Brassica napus L.)

Nine inbred lines of rapeseed (Brassica napus L.) used as male were crossed to five recessive genetic male sterile (RGMS) lines used as female to produce 45 single crosses. The crosses, their parents and a check hybrid were tested at two locations during 2007 to 2008 for testing the performance and heterosis of hybrids for seed yield and other characters. Results showed that variations for seed yield, oil content, days to flowering and days to maturity were significant. Mean squares for hybrids were significant for all characters. High heterosis (-4.5%-88.3%), heterobeltiosis (-15.6%-81.1%) and standard heterosis (-34.8%-33.1%) were found for the seed yield. The highest heterosis and heterobeltiosis were found in the cross QH303-4A×1190. The highest standard heterosis was found in the cross Qianyou8A×Q034. Both positive and negative heterosis of single crosses were detected for the oil content. Small heterosis was found for days to flowering and days to maturity. Among parents, Ⅲ188, Ⅲ224, and Q034 were proved to be the superior for seed yield when used as parents in most of the hybrid combinations. 2365, Ⅲ224, and QH303-4AB were good for high oil content breeding. Ⅲ176, 2313 and Qianyou3AB were good for the early hybrid breeding. Total 11 hybrids yielded higher than 2 500 kg•hm^(-2) and also gave significantly positive heterosis, heterobeltiosis and standard heterosis. Among them, 10 crosses gave higher oil content than that of check. These crosses can be used in the future breeding program for the seed yield and the oil content. Two crosses including Qianyou3A ×Ⅲ 224 and Qianyou3A×2313 can be used for the early breeding program.