Heterosis in Balsam

A diallel experiment of 5 parents of balsam (Impatiens balsamina L.) double was conducted to select most promising lines having more number of double flowers of large size. The characters included for investigation were plant height, number of branches per plant, number of flowers per plant, number of petals per flower and size of the ffower. Heterosis was observed for all characters and the performance of F₁ hybrids was better than the top parent. The m.s.s. for g.c.a. was higher than that of s.c.a. Gene action was found additive in nature without any epistasis for all characters except flowers per plant where epistasis was of complementary nature. The association of excess of recessive genes with high values was observed for all characters.

Though appreciable heterosis was observed for all characters, in the absence of convenient and economical method of F₁ seed production, it is better to fix the economic factors (especially because of the additive nature of the genetic variance observed for the characters) by selection in F₂ and further generations. After isolating the pure lines with superior economic characters, these lines may be further crossed to exploit the heterosis, whenever proper techniques are developed in balsam (Impatiens balsamina L.) for commercial production of F₁ hybrids.