Genetic aspects of some carotenoids synthesis in tomatoes

The wild species of tomato,Lycopersicon minutum, carries a factor which after introduction into cultivated varieties ofL. esculentum results in an increasing concentration of β-carotene in fruits. The factor is closely linked to the sp+ gene in chromosome 6 (0.12 % c.o.). This allows to conclude that it is either the B gene or a very similar allele. (The fruit flesh ofL. minutum is greenish white and contains very small quantities of carotenoids; this is perhaps due to the absence of the r+ gene). The results of the present study and findings of other workers suggest that the gene B occurs in all species of the genusLycopersicon and only a part ofL. esculentum and a part ofL. pimpinellifolium are the exceptions in having the allele B+.