FOLIAR BORON ENHANCES LEAF CHLOROSIS AND DOES NOT AFFECT PECAN PRODUCTION AND NUT QUALITY

Abstract

The narrow range between boron (B) deficiency and toxicity compared with other micronutrients is a serious problem for sustainable production of pecan throughout the southwest United States of America. However, performance of pecan under foliar B is lacking. Five B treatments (0, 0.5, 1.0, 1.5 kg B ha⁻¹, water spray) were applied to 27 years old trees of pecan variety Wichita at Leyendecker Plant Science Center, College of Agricultural, Consumer and Environmental Sciences, New Mexico State University, Las Cruces, New Mexico, USA in 2004. Foliar B significantly increased leaf necrosis, decreased number of leaves branch⁻¹, but showed no effect on number of nuts at harvest, total nut weight, weight kernel⁻¹ and nut quality. Leaf necrosis showed positive correlation with number of nuts at harvest, nut quality and negative correlation with number of leaves, total nut weight and weight kernel⁻¹. Positive correlation of number of leaves was noted with total nut weight and weight kernel⁻¹, while it was negative with number of nuts at harvest and nut quality. Number of nuts at harvest showed positive correlation with nut weight and nut quality, while it was negative with weight kernel⁻¹. This suggests that B is available in sufficient quantity and the growers can get maximum production of good quality pecan in the southwest without foliar B application provided growth, nut yield and nut quality are not limited by other essential nutrient elements.

Keywords:

• foliar B
• leaf chlorosis
• leaves
• nut yield
• quality
• pecan

ACKNOWLEDGMENTS

Financial support from Higher Education Commission, Islamabad and New Mexico State University Agriculture Experiment Station, Las Cruces is greatly acknowledged.