Genetic Progress for Yield and Yield Components and Reaction to Bean Anthracnose (Colletotrichum lindemuthianum) of Large-Seeded Food Type Common Bean (Phaseolus vulgaris) in West Shoa Zone, Ethiopia

Abstract

Fourteen common bean (Phaseolus vlgaris L.) varieties that were released in Ethiopia from 1997
to 2012 were evaluated as large-seeded food type common bean varieties with the specific objectives to:
(1) estimate the genetic progress made in 15 years of common bean breeding in Ethiopia; (2) assess
changes in associated traits in the genetic improvement of common bean varieties released in Ethiopia;
and (3) assess the reaction of common bean varieties to bean anthracnose [Clletotrichum lindemuthianum
(Sacc. & Magnus) Briosi & Cavara]. The study was conducted at two locations, Bako and Gute during
2014/2015 main cropping season in a randomized complete block design (RCBD) with three replications.
Days to 50% flowering (DF), Days to 90% maturity (DM), Grain filling period (GFP), Hundred Seed
weight (HSW), Biomass yield (BMY), Grain yield per plot (GY), Harvest index (HI), Biomass production
rate (kg/ha/day), Seed growth rate (kg/ha/day), Grain yield per day (kg/ha/day) and Anthracnose (1-9)
scale data were collected on plot basis and Plant height, Number of pods per plant, Number of seeds per
pod, Number of seeds per plant and grain yield per plant data’s were collected on plant basis. Statistical
data analyses were performed for biomass yield, grain yield, seed weight, harvest index and bean
anthracnose severity. Combined analysis of variance showed highly significant differences among the
common bean varieties and between test environments for hundred seed weight. The VXL interaction of
seed weight did not show significant difference among the varieties. Regression analysis of mean
performance at both environments on year of varietal release showed positive relationship for seed
weight (r = 0.08), biomass yield (r = 0.04) and anthracnose disease severity (r = 0.10) but negative
relationship for grain yield (r = -0.38), and harvest index (r = -0.37). The highest overall locations mean
average of grain yield was 2679.5 kg ha-1 for Ayenew and the lowest was 1050.2 kg ha-1 for GLP-2, the
grand mean being 1806 kg ha-1. The annual rates of genetic progresses were 12.7 kg ha-1 (0.13% ha-1 year-
1), -48 kg ha-1 (-0.39%), 0.68 g 100 seed-1 year-1 (0.34% 100 seed-1 year-1), -0.004% and 0.39% for biomass
yield, grain yield, seed weight, harvest index and anthracnose disease severity, respectively. Generally, the
grain yield was reduced in the period of genetic improvement, due to the consistent performance of the
reference variety Gofta. Stepwise regression indicated that grain yield day-1 (82.5%) and days to mature
(21.8%) explained more for the variation of grain yield; but, seed size (-40.2%) was more important cause
for grain yield reduction than bean anthracnose (-9.3%). The yield of large seeded food type common
bean varieties were reduced due to anthracnose and its large seeded for the last fifteen years (1997- 2012)
of breeding; in future also managing the disease; especially, anthracnose disease will be the crucial and
Ayenew (26.79.5 kg ha-1), Gofta (2627.1 kg ha-1) and Fedis (2180.6 kg ha-1) will be recommended for the
area.