Evaluation of maize (Zea mays L.) genotypes with multiple resistance to striga hermonthica (Del.) benth and striga asiatica (L.) kuntze
Date
2016
Authors
Hacholi, Kaubi Naomi
Journal Title
Journal ISSN
Volume Title
Publisher
University of Zambia
Abstract
Striga asiatica is a noxious, obligate hemi-parasite of cereal grasses that causes grain yield
losses in susceptible maize genotypes in Southern Africa. The development of host plant
resistance is one of the most practical Striga control strategies. A study was carried out to
identify genotypes that were resistant to Striga asiatica, and to investigate the mechanism of
resistance of selected genotypes of maize to Striga asiatica. A total of 14 maize genotypes
comprising of 12 developed by IITA with resistance to Striga hermonthica (causes grain
yield losses in susceptible maize genotypes in West Africa) and two locally grown maize
genotypes with unknown reaction to Striga hermonthica were assessed through field and
laboratory experiments. The field experiment was conducted at Lundazi, Katete and at the
UNZA field station during the 2013/14 farming season; while the laboratory experiment was
conducted at the IITA biosciences laboratory. Grain yield, Striga Damage Rating (SDR)
representing the reaction to Striga in the field, Striga count, plant height, cob length and cob
diameter, days to 50% flowering and days to maturity were measured or derived from the
field. Significant differences (p<0.05) were detected among the genotypes for grain yield
with the highest yield being obtained from genotype 1113-13STR (8.68 T/ha) and the lowest
for genotype 8338-1 (5.64 T/ha). Genotypes were not significantly different for SDR across
locations. A highly significant and negative correlation was observed between grain yield and
SDR (r= -0.29**). A non-significant and negative correlation was also observed between
grain yield and Striga counts at 14 weeks after planting (WAP) (r= -0.056). Positive
correlations were observed between grain yield and cob diameter (r= 0.908***), cob length
(r= 0.55***), days to 50% flowering (r= 0.4***) and days to maturity (r= 0.4***). A
significant positive correlation for Striga counts was observed between sampling stage 10
WAP and 12 WAP (r= 0.85***) and also between sampling stage 12 WAP and 14 WAP (r=
0.93***). A negative correlation was observed between SDR and plant height (r= -0.37***)
Maize genotypes 1113-13STR, 1113-3STR and 1113-2STR were identified as the most
resistant genotypes based on the fewer Striga numbers per plant produced, lower SDR scores
(scores of 1-4) and were higher yielding. These genotypes also produced lower germination
stimulants which did not favour Striga germination. The three genotypes can be used in the
improvement of resistance to S. asiatica in maize genotypes.
Description
Master of Science in Agronomy
Keywords
Agricultural innovations--Zambia , Asiatic witchweed