Ninety-nine dura x pisifera progenies (genotypes) from six seed producers (populations) in Malaysia were subjected to three fertilizer treatments after field planting in 1983. The fertilizer treatments were half, normal and twice the standard estate rate. Yield recordings and bunch analyses were taken between 1987 and 1998. Analyses of variance (ANOVA) for fresh fruit bunch (FFB), bunch number (BNO) and average bunch weight (ABW) showed significant differences for fertilizers, populations and genotypes. In addition, FFB differed significantly for genotype x fertilizer (GxF) interaction. Generally, FFB would increase at twice the estate fertilizer rate, but reducing the normal rate to half did not reduce the yield significantly. Despite improvements in ABW, reduction in FFB was due to lowering of BNO. Conversely, an increase over the standard fertilizer rate did not affect BNO. Populations 4 and 2 were high in FFB due to higher BNO and higher ABW, respectively. Progenies 4062, 4056 and 6094 shared the highest yields at half, standard and twice the standard estate rate, respectively.
ANOVA for bunch quality components was carried out and significance was detected for the populations and genotypes. Variation between fertilizers was significant for mean fruit weight, oil to bunch and kernel yield (KPY). High values for these characters along with FFB were advantages in certain populations and genotypes for higher total economic product (TEP). Highest TEP within the normal fertilizer level was recorded in Population 3, and at the altered levels was Population 4. Progeny 4051 was outstanding for TEP at half the fertilizer rate, Progeny 4056 at normal level and Progeny 5073 at twice the estate standard rate. Populations 4 and 2 offered prospects for higher oil yields at half the fertilizer cost, while Population 5 might be advantageous in lauric oil production