Variation in seed color and relationship to oil content in a yellow-seeded landraces in Brassica rapa L

摘要

Ya'an Yellow Rape is a long, widely planted landrace ofB. rapa L. in Ya'an district, a western mountainous area in Sichuan Province, People's Republic of China. It possesses a number of desirable characteristics such as early maturity, tolerances to barren soils and to dim and wet weathers, high rates of yellow seeded plants and high oil content. From 2004 to 2006, consective observations were done to investigate the variation in seed color and oil content in the population, also the relationship of seed color with oil content. The results showed that: (1) Seed colors in the population can be roughly classified into two kinds, i.e.,yellow color and brown color. Yellow -seeded plants constituted a majority of the population (76.67～78.33%). The ratio of yellow seeded plants to brown seeded plants was about 3:1. (2) Seed color in a single plant was uniform. Namely, yellow-seeded plants bore yellow seeds only, while brown-seeded plants bore brown seeds only. (3) Seed color in the yellow-seeded plants could be further subdivided into three types: pale yellow, fine yellow and brownish yellow. Oil contents of the different yellow seeds were,however, not considerably different. (4) The average oil content of yellow-seeded plants was remarkably different (3.45%) from one of brown seeded plants, but the distribution ranges of the two types of plants in oil content were overlapped. (5) It was supposed that the yellow seed trait of the landrace was controlled by a dominant gene and the oil content was controlled by both major qualitative gene(s) and minor quantitative genes. (6) A preliminary selection only based on the oil content was made and a considerable progress in rate of yellow seeded plants and oil content was obtained. The investigations also showed that there was a great variation in both seed color and oil content in the population. Further selection can be effective for improvement of oil content in this population.