COMBINING ABILITY AND HETEROSIS OF SOME PUMPKIN INBRED LINES

Abstract

The study was conducted to assess the magnitude of heterosis in pumpkin(Cucurbita moschata Duch. ex Poir.) during the period from 2011 to 2013 at the vegetable research farm of Horticultural Research Institute, Agricultural Research Center (A.R.C.), Kaha, Kalubia Governorate,Egypt. The genetic materials consisted of four parentspumpkin (cucurbita moschata viz), Long Island Cheese (P1), Tan Cheese (P2), Golden Hubbard(P3), Waltham Butternut(P4)and twelve hybrids. Parents received from Holland as inbred lines. Heterosis and performance of hybrids were estimated for several characters, such as vine length, number of branches/vine, number of leaves, number of fruits/vine, average fruit weight, fruit length, fruit diameter, cavity length, cavity diameter , flesh thickness and yield/vine. The results revealed that parents P3 and P4 recorded the highest and significant performance for number of branches, number of leave, fruit weight, flesh thickness and yield/vine. Parents P2 and P4 exhibited high number of fruits/plant, in addition to a small cavity. Crosses P1×P4 and P4×P2 recorded the highest performance for number of fruits/plant, crosses P1×P4 and P3×P1 gave the best performance for fruit weight and yield/vine, respectively. The maximum significantmid parent(MP) heterosis values (164.65%) for number of leaves /vine , (134.85%) for yield /vine, (62.17%) for flesh thickness, (54.83%) for fruit length, (41.75%) for number of fruit,(41.75%) for number of branch and (39.25%) for fruit weight. The general combing ability (G.C.A.)effects and specific combing ability (S.C.A.) effects were estimated for four parents and 4 x 4 complete diallel crosses with reciprocals respectively. Keywords:Pumpkin,Cucurbitamoschata, inbredline,diallel- cross, heterosis,combiningability.