Correlations between Cactus Pear (Opuntia spp.) Cladode Nutrient Concentrations and Fruit Yield and Quality

Abstract

A non-irrigated, Texas field trial examined correlations between cactus pear fruit characteristics, with and without 100 kg ha^-1 each of N, P, K, and cladode concentration' of N, P. K, Ca, Mg, Na, Fe, Zn, Mn and Cu. Seven Mexican fruit clones of cactus pears were used. While 100 kg ha^-1 N, P, K did not significantly influence fruit yield, it significantly increased the fruit sugar (soluble solid) content. Different results emerged depending on whether the correlations were based on the mean of many cladodes per plant or at the individual cladode level. At the whole plant level. cladode tissue Nand K concentrations were positively correlated with fruit yield and Na concentration was negatively correlated with fruit yield. Mg concentration was correlated positively with fruit sugar content. The optimum Mg content was estimated to be 2.2%. Correlations also werc assessed for 5 accessions between fruit number per cladode and the nutrient content of the cladode. Cladode K concentration was negatively correlated with the number of fruit on the same cladode for 2 of the 5 accessions. For only two of the five accessions, fruit number per cladode was correlated with cladode P concentration. The relationships between fruit production or quality versus cladode concentrations were very different for these clones. It may be necessary to develop individual fruit quality or production relationships for individual cultivars.