Genotypic competition in field beans (phaseolus vulgaris L) varieties
Abstract
Beans in Kenya are normally grown by small scale
farmers in mixtures for subsistence agriculture. These
mixture often comprise landraces or improved
cultivars. Farmers do not select the most sui table
cultivars for the combination in this system of
cultivation. There is also little information
available on the effects of competitive interactions
on the production of such mixtures. This study was
designed to study genotype interactions and hence
analyse the effect of competition on the performance
of established bean cultivars. It was therefore to
identify the varieties best suited to varietal mixture
production systems in the peasant farming sector.
Four established bean cu l, tivars namely Rosecoco,
Canadian Wonder, Red Haricot and Mwezi Moja planted in
Kenya were used in this study. The four varieties were
used to develop six biblends and each biblend
comprised of equal proportion of the component
varieties. The biblends and uniblends formed a total
of ten treatments which were planted in a randomised
compete block design at Kabete, Kakamega and Bukura.
Genotype competition analysis was done according to
model presented by Federer et al., (1982).
(xi)
It was evident from the study that there was
genotypic interaction in the mixtures studied. Four
forms of competition as described by Schutz et al.,
(1968). namely neutral effects, overcompesation
(cooperati ve), undercompesation and compl imentary were
observed. Among these interaction forms
overcompesation was considered as the most important
interaction form as it clearly pointed at yield
advantage. Competi tive abil ity of various genotypes
showed awider variability over seasons and locations.
Ii is therefore recommended that the results from one
location or season can not be used in another before
it is tested. For Kabete short rains Canadian Wonder
and Mwezi Moj a would be considered favourable. For
Kabete during the long rains, however none of the
mixture combinations for yield was favourable. For
long rains at Kakamega, mixture combination of
Rosecoco and Red Haricot and Rosecoco and Canadian
Wonder combination could be adapted. At Bukura
Rosecoco and Red Haricot combination and Rosecoco and
Mwezi Moja mixtures may be favourable combinations
Citation
Master of science in plant breedingPublisher
University of Nairobi Department of Crop Science