TEMPERATURE EFFECTS ON SEED COLOR IN BLACK-SEEDED AND YELLOW-SEEDED RAPESEED

The effects of growth temperature on seed color of two black- and four yellow-seeded doubled-haploid genotypes of Brassica napus were examin ed with plants grown at 16/12, 18/14, 20/16, 22/18 and 24/20-degrees-C (day/night). High temperatures significantly reduced seed color that developed on yellow-seeded genotypes but did not alter seed color prod uced on black-seeded genotypes. The decrease in pigmentation measured with a modified near-infrared reflectance analyzer was linearly relate d to temperature for the yellow-seeded genotypes. Significant differen ces in the magnitudes of the response were observed among the yellow-s eeded genotypes. This is the first systematic study of temperature eff ects on seed color in rapeseed. The results confirm previous prelimina ry reports of environmental modifications of this trait. The study als o illustrates a method for determining temperature effects on seed-col or expressivity that may be useful for plant breeding programs.