CORRELATION AND REGRESSION ANALYSIS OF SQUASH PUMPKIN (Cucurbita maxima L.) IN RESPONSE TO DEFOLIATION SEVERITY AND MANURE RATE IN SAMARU, ZARIA

Two field trials were conducted in 2012 and 2014 on the experimental farm of the Institute for Agricultural Research, Ahmadu Bello University, Samaru, Zaria (110 111 N, 070 381 E, 684 meters above sea level) to study the association of some growth and yield characters of two varieties of squash pumpkin (Cucurbita maxima L.) to severity of defoliation and farm yard manure (FYM) rates. Regression study was also used to obtain the optimum level of FYM and defoliation severity. The treatments consisted of three degrees of defoliation (0, 25 and 50%), three levels of farm yard manure (0, 5 and 10 t ha-1) and two varieties (Yar-Madina and Ex-Ajiwa) of pumpkin. The defoliation severity of the pumpkin was imposed at 6 weeks after sowing (WAS) starting from the bottom towards the apex. The treatments were laid out in Randomized Complete Block Design (RCBD) replicated three times. The correlation result indicated that leaf area (LA) and relative growth rate (RGR) were the highest contributor of fruit yield. Other characters that contributed to the fruit yield include; crop growth rate (CGR), vine length, leaf area index (LAI) and fruit circumference. The regression analysis showed a quadratic response of fruit yield per hectare to defoliation severity which indicated that the optimum defoliation severity that pumpkin can tolerate was attained at 25% while linear responses was observed on FYM rates, indicating that the optimum levels was not obtained at 10 t ha-1.