DIFFERENTIAL RESPONSE OF FIFTEEN PINTO BEAN CULTIVARS TO TWO NITROGEN RATES

Authors

A. Alhasan, University of Wyoming
J. Heitholt, University of WyomingFollow

Document Type

Article

Date of this Version

3-2017

Citation

ANNUAL REPORT OF THE BEAN IMPROVEMENT COOPERATIVE, No. 60, March 2017. Published by USDA.

Comments

U.S. government work.

Abstract

INTRODUCTION - Dry bean (Phaseolus vulgaris L.) is the main source of protein (20 to 25%) for most people in the world; protein from soybean is higher but is primarily use for livestock. Dry bean yield is often lower than 1000 kg ha^-1 in most dry bean producing regions except the US. Besides drought, low soil fertility and ineffective nitrogen (N) management strategies are the most important yield-limiting factors for dry bean production worldwide (Fageria et al., 2013). Use of N-efficient dry bean genotypes, optimal timing of N application(s), and identifying a costeffective N rate are good strategies to optimize dry bean profitability. Therefore, the aim of this study was to evaluate fifteen pinto bean cultivars grown in the greenhouse with two rates of nitrogen fertilizer for physiological/growth traits and their tolerance to low N.

MATERIAL AND METHODS - Seed of (Bill Z, Centennial, CO46348, COSD-25, COSD-35,Croissant, El Dorado, ISB1231-1, La Paz, Lariat, Long’s Peak, ND307, Othello, Poncho, and UIP-40) were sown in 11.3 L pots (8 kg of soil) in the greenhouse (four pots per cultivars) on 20 September 2016 in Laramie WY (2200 m elevation). Seed were inoculated with a commercial inoculant at planting. The soil mix was 33% sand, 33% soil amendment, and 33% native soil. Seedlings were thinned to three per pot at two weeks. Aqueous fertilizer treatments (NH4NO3) were applied at (25, 32, 39, and 46 days after planting, dap) in two rates (0 and 67 kg N ha^-1 seasonal equivalent). A randomized complete block design was used with two replicates. Leaf chlorophyll (CHYL) was measured on the third uppermost fully-expanded leaf by using a chlorophyll meter (SPAD-502) at (26, 33, 40, 47, and 54 dap). The height, root mass, and stalk mass was determined at maturity. Seed yield, pod harvest index (PHI), and nitrogen susceptibility index (NSI) were also determined at maturity. Pod harvest index equaled seed weight divided by the sum of pod wall plus seed weight; NSI was calculated as the cultivar’s percentage reduction in yield due to zero N divided by the average yield reduction due to zero N.