Biophysical basis of resistance in bitter gourd against melon fruit fly, Zeugodacus cucurbitae Coquillett (Diptera: Tephritidae)

Abstract

Melon fruit fly (Zeugodacus cucurbitae Coquillett) is one of the most important pests of cucurbits and bitter gourd (Momordica charantia Lin.) is highly prone to damage by this pest worldwide. Field and laboratory experiments were conducted to screen the bitter gourd accessions for their reaction to melon fruit fly. Screening was carried out with 50 bitter gourd accessions (wild types and commercial cultivars) and among these, 12 accessions (2 resistant, 6 moderately resistant, 3 susceptible and 1 highly susceptible) were selected to study the influence of morphological traits on larval density and reaction to melon fruit fly. The fruit weight, fruit length, spine length and spine density were positively correlated with fruit damage while the fruit width was negatively correlated (-0.2427 and -0.2621) at phenotypic and genotypic levels. The fruit hardness had a significant negative correlation (-0.9046 and -0.9205) to fruit damage at the phenotypic and genotypic levels.