Genotypic variation in the response of sorghum to intercropping with cowpea, and in the effect on the associated legume

Abstract

Genotypic variation in the response of sorghum to intercropping with cowpea, and in the effect on the assocíated legume. Field Crops Res., 14: 263-290. Selectíon of sorghum genotypes for the sorghum-cowpea intercrop system would be simplifíed íf it could be done in sole crop. In order to compare evaluation in sole crop and in the presence of the standard cowpea cultivar C 152, sorghum ínbred lines, F, hybrids and land races whích díffered in maturíty date, heíght and canopy characters were grown in the two systems in two seasons at Hyderabad, India. Cowpea sole crop was included as an additional treatment. Sorghum canopy characters and yield components in intercrop were highly correlated with the same characters in sole crop. However, multiple regression of sorghum grain yíeld ín intercrop on characters measured in intercrop explained more variation than regression on characters measured in sole crop. Characters related to Iight interceptíon were the most influential in determining sorghum yield, but some genetically determined varíation ín yield was unexplained by either multiple regression. Characters related to light interception had a nega tive influence on cowpea yield, though agaín some variation due to sorghum genotype was unexplained. Thus although the influence of sorghum plant characters on each component crop is predictable, comperfsation between the components makes the overall outcome more dífficult to predíct, and dependent upon which component is favoured by the environment. The sorghum genotypes selected will therefore represent a compromise: they should not be dwarf types, but should be early maturing to escape drought, and have narrow canopies 80 as not to be too competitive on the cowpea. The final selection should be made in intercrop.

Genotype Effects in Millet/Cowpea Intercropping in the Semi-arid Tropics of Niger

“…As in 1984, the grain yield of cowpea was greatest when intercropped with the dwarf pearl millet genotype 3/4 HK. Similar observations have been made previously by Andrews (1974) and Galway et al (1986). …”

The Effects of Sorghum and Cowpea Genotype and Sorghum Sowing Density in an Intercrop System

“…The intercrop sorghum genotype had no significant effects on the associated cowpea, contrary to the results of previous experiments (Galwey et al, 1986;de Queiroz, 1984). This may be because the other experiments were conducted in the rainy season whereas the present experiment was conducted in the postrainy season when the weather did not allow extensive sorghum canopy development.…”

“…The response of sorghum genotypes to intercropping with cowpea, and their effect on the associated cowpea, is largely determined by morphological and developmental aspects of the sorghum plant, many of which can be determined in a sole crop (Galwey et al, 1986). Moreover sorghum genotype X environment interactions in intercrop are related to those found in sole sorghum t Present address: CPATSA/EMBRAPA, Caixa Postal 23, 56300 Petrolina (PE), Brazil.…”

Genetic variances, heritabilities and genetic correlations of grain yield, harvest index and yield components for common bean (Phaseolus vulgaris L.) in sole crop and in maize/bean intercrop

“…Furthermore, genotype × cropping system interactions are frequently encountered when a crop is grown in sole crop and intercrop, and these interactions are to the detriment of the dominated/understorey crop such as common bean (Davis and Woolley 1993). These interactions, though interesting, remain to be addressed through plant breeding (Galwey et al 1986;Smith and Zobel 1991).…”