Development of Male and Female Parents of F1 Hybrid in Chinese Cabbage

Abstract

The experiments aimed to improve and select male and female parents which had high self incompatibility and gave good hybrid varieties. Hybrid seed production by bees was also studied. Inbred seeds of 4 Chinese cabbage lines were produced by bud pollination which was a conventional technique for inbred lines. Results showed that line 40-9 gave the highest seed weight, 0.165 grams per plant. Seed set analysis and fluorescent microscope techniques were used to check self incompatibility of 9 lines of Chinese cabbage. Seed set analysis showed that all lines were self incompatible. However, when fluorescent microscope technique was used, not all lines were self incompatible, such as lines 23, 23-3-1, 40 and 142-5 showed weak self incompatibility. The 4 inbred lines with self incompatibility were selected to be studied in seed production. Reciprocal crosses (by bee pollination) showed that when line 40-9 was used as a female parent, they gave the highest seed yield. Crosses 40-9x142-5, 40-9x27-3-7 and 40-9x 23-3-4, gave high seed weight: 4.8, 3.9 and 2.7 kilogram per rai, respectively. Eleven hybrid varieties of Chinese cabbage were tested in comparison with the 3 commercial varieties in winter 1998 at Department of Horticulture, Chiang Mai University. It could be concluded that hybrid 142-5x40-9 gave the highest head yield, 6,170 kilogram per rai. It yielded 36.3% higher than commercial varieties. Other crosses such as hybrids 23x27, 23x142, 27-3-7x 23-3-4, 27-3-7x142-5 and 40-9x23-3-4 had good horticultural characteristics. They yielded 4,646,5,551,3,665,5,150 and 3,785 kilogram per rai, respectively. Therefore their parents should be improved for a good F₁ hybrid in the future.