No abstract

Effect of five planting patterns on the growth, yield and yield components of intercropped sunflower and sorghum was studied during 1989-90 planting seasons at University of Maiduguri, Nigeria. Generally, intercropping depressed the performance of sorghum more than sunflower. Sorghum plants grown in alternate hills with sunflower had the shortest stems, the least dry matter and total seed yields per hectare, while the highest dry matter and seed yields were obtained from sorghum planted in five alternating rows with sunflower. Similarly, in sunflower, plants grown in five alternating rows with sorghum had the highest yields compared with other planting patterns, but there were no significant differences in the dry matter and total seed yields of sorghum and sunflower intercropped in three and five alternating rows. Light transmission, leaf area index and yields of both crops followed similar trends under the various planting patterns. Interplanting in five alternating rows that allowed the highest leaf area also allowed the lowest light transmission and produced the highest yields. Land use efficiency was highly improved under three and five rows mterplanting by 52 and 74 % respectively.

Fifteen selected okra varieties consisting of ten newly-developed lines and five established varieties were evaluated for stability of seed yields in eight different environments i.e. several monthly plantings for three consecutive years. Seed yield data were analyzed to determine the effectiveness of using different planting dates in seed yield trials of new okra varieties. The wide ranges of environmental indices ( -10.8 to 24.4) and seed yield (2.7 to 38.0 g plant"') indicated significant variation between the environments even though the trials were conducted at the same location. A regression method of stability analysis showed that the mean differences between environments, the varieties and their interactions were highly significant. These results suggest that where limited resources prevent the use of several locations, different dates of planting for two or more years could be used to evaluate okra varieties for seed yield without losing much information on their relative ranking.The interaction of genetic and environmental effects on crop performance, usually referred to as the genotype x environment (G x E) interaction, is of great concern to plant breeders seeking to develop new crop varieties. The presence of G X E interactions causes difficulty in getting a reliable estimate of hentability and predicting the rate of genetic progress under selection for a particular character.The common practice adopted by breeders to minimize the biases resulting from G X E interaction is to subject the new varieties to multilocation performance tests (Al I ARU 1961;Al EARD and BRAUSIIAW 1964) for several years. This helps to identify varieties which give superior performance over a wide range of environments. However, the scarcity of research funds in the developing countries has reduced the possibility of conducting such tests in an adequate number of locations and years. The cheaper alternative is the unilocation test under different micro-environmental conditions created by varying plant density, fertilizer rates and planting dates. This paper reports the results of seed yield trials involving 2 to 3 monthly plantings of fifteen okra varieties, conducted at

A two-year study considered the effect of pod harvesting intervals of 3, 5, 7, 9, 11 or 20 weeks after pod set (WAPS) on the relationship between the physical condition of the pods, seed maturation and quality in fluted pumpkin (Telfairia occidentalis). Pod characteristics, such as the intensity of bloom wax on the pod and stiffness of the pod ridges, showed perfect linearity and correlation with the age of the pod, whereas changes in seed quality factors – germination, dry matter, oil and protein concentrations were curvilinearly associated with the time of pod harvest. Thus, seed quality factors increased steadily up to nine WAPS then declined. The point at nine WAPS defined as physiological maturity for fluted pumpkin seed and approximate visible indications of this point in the field were fairly stiff pod ridge condition and fading of bloom wax.