Effects of excess nitrogen on growth, flowering and fruit set of bell pepper (Capsicum annuum L.)

Field experiments were conducted on a Flanagan Silty Clay Loam to investigate the influence of excess N at transplanting a growth, yield and fruit set of bell pepper (Capsicum annuum L. cv. 'Lady Bell'). The rates were 112, 224, 336 and 448 kg N/ha. Excess N at transplanting did not stimulate vegetative growth, but rather suppressed plant growth, particularly at early growing period. In general, plants exhibiting poor early growth produced lower early and total fruit yield. Excess N (336 and 448 kg N/ha) reduced the total number of fruits per plant by as much as 48 to 57% at early harvests. The percentage of fruit set decreased linearly as N rates were increased. Fruit set was correlated negatively with total leaf N and positively with plant weight, suggesting that higher leaf N content and lower weight of plant grown with excess N were detrimental to fruit set and yield of bell pepper.In sand culture experiments under controlled environmental conditions and ammonium nitrate as the N source, excess N (800 ppm) reduced the total number of fruits and resulted in lower percentage of fruit set. High total leaf N but lower sugar content in plants grown with excess N were probably attributed to low fruit set, since they were found to be correlated. Excess N can reduce flower bud production when applied during the period between transplanting and first anthesis. In addition, excess N caused reduction in fruit set regardless of when it was applied. The period prior to first anthesis was the most sensitive plant stage. Flowers at or after anthesis and immature fruits were more subjected to abscission than at flower bud stage. Abscission of flowers and immature fruits continued to occur in response to excess N although the plants had reached physiological maturity. Pepper plants do not exhibit a distinct separation between juvenility and maturity phases.U of I OnlyETDs are only available to UIUC Users without author permissio