EFFECTS OF MUTATION FOR PHOTOPERIODIC RESPONSE ON TOBACCO PLANT DEVELOPMENT IN ISOGENIC LINES

Abstract

Crosses were made between the flue-cured tobacco cultivar Delcrest and a short-day line, Mammoth Delcrest G.5, developed from a spontaneous mutation in Delcrest. Four sets of crosses were used, each set consisting of six genetic populations, viz. P1 (Delcrest), P2 (Mammoth Delcrest G.5), F1 (P1 × P2), F2 (F1 selfed), B1 (F1 × P1), and B2 (F1 × P2). The data observed on flowering time were in good agreement with the postulated monofactorial segregation of normal (day-neutral) against short-day plants, the latter being homozygous recessive. The mean flowering time of the first filial generation was very close to the Delcrest parent but the difference was still significant. The mutant gene apparently had no differential effect on the dimensions of the bottom and mid-stem leaves, but towards the top of the plant incomplete dominance was indicated for both the width and length of the leaves.