Identification of the most suitable tester(s) from among parents of elite bitter gourd (Momordica charantia L.) single cross hybrids

In hybrid crop breeding programmes, the choice of tester is vital for efficient selection of experimental inbred lines for their potential in hybrid combinations. To identify such testers, 10 bitter gourd advanced breeding lines (ABLs) were crossed to five candidate testers. The resulting test cross (TC) hybrids were field-evaluated for fruit yield, fruit diameter, and fruit length in a two-replicated alpha-lattice design. Four criteria, namely (i) accuracy of ranking the ABLs, (ii) discrimination of the ABLs, (iii) high trait mean of TC hybrids and (iv) the high magnitude of gca effects, individually and in combination, were used to identify most suitable tester(s). The estimates of the correlation between ranks assigned to TC hybrids derived from each tester and those assigned to the TC hybrid mean of all five testers were used as statistics to quantify the accuracy of ranking ABLs by testers. The variance of TC hybrids derived from each tester was used as a statistic to quantify the ability of testers to discriminate the ABLs. The most suitable tester varied according to the criteria as well as the trait. Based on all four criteria, 83-031, 83-028 and 83-016 were identified as the most suitable testers for fruit yield, fruit diameter and fruit length. These testers are suggested for evaluating the performance of new experimental inbred lines developed from F2/backcross breeding populations derived from parents belonging to the same heterotic group and/or from any genetically variable source populations.