Teste de alelismo entre os mutantes de amadurecimento alcobaça e non-ripening em tomateiro

Abstract

Since the early 1980's there are conflicting reports on the possible allelic relations between the tomato ripening mutants alc (=alcobaça) and nor (=non-ripening). In order to end these controversies, a test of allelism between the genes alc and nor was performed. A total of 364 plants of the F2 population between the tomato lines TOM-559 (alc/alc) and TOM-613 (nor/nor) were screened, along with 20 plants each of lines TOM-559 (alc/alc) and TOM-613 (nor/nor), of hybrids F1 [(TOM-559 x TOM-613), alc+/alc nor+/nor], F1 [(Floradade x TOM-559), alc+/alc nor+/nor+] and F1 [(Floradade x TOM-613), alc+/alc+nor+/nor], and of the normal phenotype line Floradade (alc+/alc+nor+/nor+). TOM-559 and TOM-613 are near-isogenic lines to Floradade, and differ from the latter only due to the presence of genes alc and nor, respectively. Floradade fruit harvested at the breaker stage show normal red color (normal phenotype) when fully ripe, whereas fruit of either TOM-559 or TOM-613 remain yellow or yellowish-orange (mutante phenotype). Four fruits per plant were harvested at the breaker stage and subsequently evaluated for their mature fruit color phenotype (normal or mutant). The results of the test of allelism indicate that the most likely hypothesis is that alc and nor are allelic to each other. Therefore, alc was considered to be a third allele at the nor locus, and the symbol norA was substituted for alc.