World Journal of Agricultural Sciences 3 (5): 639-641, 2007 ISSN 1817-3047 © IDOSI Publications, 2007 Corresponding Author: Dr. E.O. Okporie, Department of Crop Production and Landscape Management, Ebonyi State University, Abakiliki, Nigeria 639 Correlation of Protein and Oil Contents with Five Agronomic Characters of Maize (Zea mays L.) After Three Cycles of Reciprocal Recurrent Selection E.O. Okporie and H.O. Oselebe Department of Crop Production and Landscape Management, Ebonyi State University, Abakiliki, Nigeria Abstract: A correlation analysis study was conducted with eight varieties of maize (Zea mays L.): Nsukka High Quality-Yellow Early (NHQ-YE); Nsukka High Quality-White Early (NHQ-WE); Nsukka High Quality-Yellow Late (NHQ-YL); Nsukka High Quality-White Late (NHQ-WL); Nsukka Quality Maize-Yellow Early (NQM-YE); Nsukka Quality Maize-Yellow Late (NQM-YL); Nsukka Maize-Yellow Early (NM-YE) and Nsukka Maize-Yellow Late (NM-YL); developed after three cycles of reciprocal recurrent selection, to find out the association of increasing protein and oil contents with five agronomic characters. The result showed that the 100-kernel weight and kernel density which predict yield components and days to 50 percent silking which predicts the maturity time of maize plants were independently associated with protein and oil contents in all the source varieties. This indicates that, these chemical constituents of maize can be increased or decreased and selected for without adversely affecting the five agronomic characters. Key words: Correlation % protein % oil % recurrent selection INTRODUCTION Jaya and Rao [9], all have at one time established the fact Maize (Zea mays L.) grains, nutritionally, is known to correlated with yield. Rajni Raman et al. [10] found oil be predominantly carbohydrate but has small proportions content to be significantly and positively correlated with of protein, oil, amylose, amylopectin and other minerals 100-kernel weight, plant height, ear height and grains [1]. These constituents can be altered genetically when yield. Therefore, there would be no serious barrier in effective breeding methods are employed. Recurrent selecting for both high protein and oil. selection method has been among the most effective and The objective of this study, therefore, is to estimate successful methods employed in the maize improvement degree of relationship, that is, the correlation between programs [2, 3]. protein and oil and plant and/or ear heights, 100-kernel Maize breeders suspect that kernel protein and oil weight, kernel density and days to 50 percent silking so as content may be negatively correlated with yield. to provide information that would guide the choice of According to Obi [3], it has not been possible in parents for developing synthetics or hybrids with high combining nutritional quality with yield probably protein and oil. because of the reduction of starch content in the grains. Panthee et al. [4], pointed out that there exists an inverse MATERIALS AND METHOD relationship between seed protein and oil concentration, making it difficult to improve both traits simultaneously. Eight varieties: Nsukka High Quality-Yellow Early (NHQ- If these statements are true, then maize breeders that are YE), Nsukka High Quality-White Early (NHQ-WE), interested in developing agronomically good varieties Nsukka High Quality-Yellow Late (NHQ-YL), Nsukka High with high nutritional quality are faced with formidable Quality-White Late (NHQ-WL), Nsukka Quality Maize- task. However, several researchers have paved the way Yellow Early (NQM-YE), Nsukka Quality Maize-Yellow toward simultaneous selection of high quality and high Late (NQM-YL), Nsukka maize-Yellow Early (NM-YE) and yielding crop varieties [5-7], working independently, Nsukka Maize-Yellow Late (NM-YL) developed from the have developed crops of high quality combined with high 3rd cycle of reciprocal recurrent selection at the yield. Also Okporie and Obi [1], Obi and Onyishi, [8] and University of Nigeria research farm, Nsukka, were used for that protein and oil contents of cereals are positively