Diallel Analysis of Some Yellow Maize Inbred Lines under Low and Normal Nitrogen Levels

• Published in: International journal of plant breeding and genetics 2015-03, Vol.9 (2), p.32-43
• Main Author: Kamara, Mohamed M
• Format: Article
• Language: English
• Subjects: Zea mays
• ISSN: 1819-3595; 2152-3347
• DOI: 10.3923/ijpbg.2015.32.43

A half diallel cross among seven yellow maize inbred lines was evaluated under low (60 kg N fed super(-1)) and normal (120 kg N fed super(-1)) nitrogen levels for six quantitative characters i.e., plant height, ear length, ear diameter, number of rows ear super(-1), number of kernels row super(-1) and grain yield plant super(-1), to estimate general (GCA) and specific (SCA) combining ability effects and their interactions with nitrogen levels as well as identify the superior inbred lines and crosses. Significant differences were detected between the two nitrogen levels for all the studied traits except ear diameter and number of rows ear super(-1). Mean squares of crosses and crossesxN interaction were significant for all the studied traits. Both GCA and SCA mean squares were highly significant for all the studied traits under the two nitrogen levels and their combined data. The ratio of GCA/SCA exceeded the unity for plant height, ear diameter, number of rows ear super(-1) and number of kernels row super(-1), indicating that these traits were mainly controlled by additive gene action. On the contrary, predominance of non-additive gene action chiefly controlled the expression of ear length and grain yield plant super(-1) under both and across nitrogen levels. Significant interaction mean squares between GCA and SCA with nitrogen levels were detected for the most studied traits. Three crosses P sub(3)xP sub(6), P sub(2)xP sub(6) andP sub(4)xP sub(7) at low nitrogen level, four crosses P sub(3)XP sub(6), P sub(4)XP sub(7), P sub(1)xP sub(3) and P sub(4)xP sub(5) at normal nitrogen level and five crosses P sub(3)XP sub(6), P sub(2)xP sub(6), P sub(4)xP sub(7), P sub(1)xP sub(3) and P sub(4)XP sub(5) at the combined data were significantly outyielded the check hybrid SC168. The inbred lines P sub(3) and P sub(4) were the best general combiners for ear length, number of rows ear super(-1), number of kernels row super(-1) and grain yield plant super(-1) under both nitrogen levels and their combined data. Six crosses i.e., P sub(2)xP sub(6); P sub(3)xP sub(6); P sub(4)xP sub(5), P sub(4)xP sub(7), P sub(1)xP sub(3) and P sub(1)xP sub(5) were distinguished specific combiners for grain yield plant super(-1) and most of its components under low and normal nitrogen levels as well as the combined data.