Heterosis potential analysis of cytoplasmic male sterile three-way crosses hybrids in Brassica napus

A comparison between cytoplasmic male sterile three-way cross and single-cross hybrids was studied in Brassica napus. The result showed that , the highest yield in all of the combinations was one single cross hybrid, the second one was three-way cross hybrid. The average yield of three-way cross hybrids was little lower than that of single cross hybrids. Comparing to the corresponding two single cross hybrids, 25% of three-way cross hybrids had higher heterosis, 41.7% of them had lower heterosis , and 33.3% of them had the heterosis between those of two single cross hybrids. The average plant CV(%) of 12 three-way cross hybrids in 7 agronomic characters had little difference between the three-way cross hybrids and single-cross hybrids except pods per plant and seeds per pod which were higher. Comparing to each three-way cross hybrid with the corresponding two single cross hybrids, the uniformity of three-way cross hybrids was worse than that of the single cross hybrids. Three-way cross hybrids had better resistance to Sclerotinia sclerotiorum and lodging than those of their corresponding two single cross hybrids.