Demand-Driven Technologies for Sustainable Maize ... - IITA

82VII, XI and V that had grain yield of 4.0 t/ha or higher. Clusters VI, XI,I, IV, XI, III, VII and V had mean protein content of 8% or more.The QPM lines in cluster VIII, although high yielding, exhibitedsome undesirable traits such as high fi bre (2.8%), moisture (6.5%)and fat (2.4%) contents. Lines in cluster V showed lower grain yieldthan those in cluster VIII but they had some desirable traits such asacceptable plant height (190cm), high percentage protein (12.1%)and low moisture, ash, fi bre and fat contents (4.8%, 1.0%, 1.8% and1.9%, respectively).The contribution of each trait to the expression of genetic divergencemeasured by D 2 values revealed that the highest contributor was plantheight (35.2%) followed by days to physiological maturity (14.9%),grain yield (8.1%), days to silk (7.8%), protein content (7.2%) and earheight (7.1%). The least contributors were carbohydrate (0.6%), fat(0.7%) and fi bre (2.1%) contents (Table 2).Inter- and intra-cluster genetic distances (D 2 ) of the 63 lines arepresented in Table 3. High values of inter-cluster D 2 statistic rangedfrom 61.2 (between cluster I and VI) to 511.7 (between cluster V andIX). Over 80% of the inter-cluster variability among these lines wasexplained by the analysis. The intra-cluster distance of 0 was obtainedfor clusters II, III, VI, VII, VIII, IX and XI, followed by 4.3 for cluster V,8.6 for cluster I, 13.2 for cluster IV and 39.5 for cluster X.Table 4 contains the number of clusters and their correspondingQPM lines. PMG007M, PMG019M, PMG029M, PMG023L andPMG028L in cluster VIII, PMG019E, PMG007E and PMG003Lmembers of cluster V, and PMG009E and PMG028E of cluster IIIwere high yielding. They exhibited other desirable traits such as highprotein and carbohydrate contents, low ash, fi bre and fat contents.DiscussionThe highly signifi cant mean square obtained in this study revealedappreciable variations among the 63 lines evaluated for 3 years.Thus, the possibilities exist for selection and further improvementof these QPM lines. The results obtained in this study indicated thatintercrossing lines from clusters V and VIII and other lines, especiallyfrom clusters III, VII and XI, could produce high-yielding transgressivesegregants for population improvement programs.Contributions of each trait to genetic diversity in this study couldbe used as selection criteria for further improvement and choice ofparents for hybridization and generate of wider variability. The presentstudy clearly indicated that progenies expected from crossing diverseparents would reveal greater diversity for crop improvement. Theseresults are in agreement with the fi ndings of Thakur and Zarger(1989) and Alagarswamy and Chandra (1998).