Journal Articles

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Journal Articles (Department of Plant and Science)

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Browsing Journal Articles by Author "Fakorede, M. A. B."

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    Estimating Kernel Weight in Maize
    (Faculty of Agriculture, University of Ife, 1981) Fakorede, M. A. B.; Orisadare, S. S.
    In an experiment involving 20 maize (Zea mays L.) cultivars and five sample sizes (100,500,750 and 1000 kernels) replicated four times, it was found that sample weight increased linearly (r2 = 0.81) as sample size increased. This suggests that mean weight/kernel did not differ significantly among sample sizes. In similar trials involving 21 S1 lines developed from two maize cultivars (FARZ 23 and FARZ 27) but utilising sample sizes of 25, 50, 75, 100 and 125, mean weight/kernel showed a curvilinear response to increased sample size with the point of inflection at approximately the sample size of 100 kernels. This suggests that mean weight/kernel was variable for sample sizes less than 100 kernels. It seems, therefore, that kernel weight in maize can be estimated from small sample sizes (e.g. 100 and 125) kernels in order to save time and expenses when evaluating a large number of lines in a breeding programme.
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    Predicted responses to recurrent selection in maize (Zea mays L.)
    (Faculty of Agriculture, University of Ife, 1979) Fakorede, M. A. B.; Obilana, A. Tunde
    Previous studies with computer simulation models have shown that standardised correlated response in one trait, y, to selection for another trait, x, should be the same in one generation regardless of whether selection is for x or for y. In the study reported herein, we tested the hypothesis that direct response to selection for trait x should be the same as standardised correlated response in trait x when selection is based on trait y. Additionally, we compared, observed and predicted correlated responses to seven cycles of reciprocal recurrent selection for grain yield in two maize populations Results obtained indicated that predictions of direct and standardised correlated responses showed poor agreement. Direct response to mass selection, however, agreed more closely with standardised correlated responses than did half-sib selection and S1 testing, whereas direct response to S1 testing agreed more closely with conventional correlated response than did the other two selection methods. Also, observed and predicted correlated response to reciprocal recurrent selection for grain yield showed poor agreement. However, predictions based on parameters obtained in the fourth cycle of selection agreed more closely with observed changes than similar estimates obtained from the original populations. Implications of these results in determining indirect selection criteria are discussed.
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    A Proposed Procedure for Rapid Development of Inbred Lines for the Production of Hybrid Maize in Nigeria
    (Faculty of Agriculture, University of Ife, 1982) Fakorede, M. A. B.
    A procedure is described for the rapid development of inbred lines to be used as parents of high-yielding hybrid cultivars of maize (Zea mays L.). This procedure involves the production of S1 lines from three unrelated populations A, B, C whose Fl hybrids are known a priori to demonstrate significant yield heterosis. The S, lines are evaluated per se and S2 lines obtained from the best performing 5 or more S1 lines from a population are intercrossed with those-from the other populations to give 75 or more S2 x S2 crosses. The S2 x S2 crosses are evaluated with check cultivars (e.g. cultivar hybrids, the best widely grown cultivar and single-cross hybrids, if available) and the top 5 are selected for the National Zonal Maize Yield Trials (NZMYT) coordinated by the National Cereals Research Institute (NCRI), Ibadan. S4 x S4 hybrids of these top 5 selections are evaluated in the NZMYT as well as several other locations available to the researcher and inbred lines of the best 1 or 2 hybrids are released as parent materials. The advantages of this procedure include (i) simultaneous inbreeding and evaluation trials, (ii) flexibility for concurrent population improvement and extraction of inbredlines, and (iii) with two rainfed cropping seasons and an off-season with irrigation facilities, near-homozygous inbred lines (F 0.99) can be obtained within 3 calendar years.