Sawant, A. C.
L. escelentum and L. hirstum were used as female and male parents respectively, the former providing six marker genes -- a, c, sp, ms\2, Wo and d. From the later two entities were used -- L. hirsutum, F. glabratum and typical L. hirsutum.
In F1 esculentum x glabratum the percentage of fruit-set is higher than in F1 esculentum x typical hirsutum, though both these crosses have a considerably lower fruit-set than the intraspecific cross. The same relationship holds true with respect to seed-set. In segregating progenies a and c show significant deviations when typical hirsutum is used as the male parent, but the segregation is normal when glabratum is used as the male parent. The segregation of sp and ms\2 is abnormal in both crosses but the deviations are stronger where glabratum is used as the male parent. This is partly due to the complementary semilethal factors in the esculentum x glabratum cross (TGC 4:18).
Wo and d, which are linked, show normal segregation in both crosses. However, the crossing over between them is significantly lower when typical hirsutum is used as the male parent than when glabratum is used as male parent or in pure esculentum.
These genetic findings are corroborated by cytological observations. Esculentum x typical hirsutum F1 shows significantly lower chiasma number for the whole complement as well as for second chromosome on which Wo and d are located than in F1 esculentum x glabratum and the parents. In F1 esculentum x hirsutum pollen abortion is significantly higher than in F1, esculentum x glabratum or the parents.
Taking into consideration these cytogenetic observations and the differences in characters between glabratum and typical hirsutum, it is evident that the classification ot these two entities should be reconsidered.