The Effect of Full-sib and Half-sib Family Selection Methods on Three Level Protein of Maize Population Ghouta2

Ramez Hsean
General Commission for Scientific Agricultural Research-
Homs Research Center
Tishreen University, Faculty of Agriculture
2007

Abstract

Improvement of protein content in maize populations is the important objectives for plant breeder. Two selection methods (full-sib family and half-sib family selection) were applied on maize population G-2 during two successive seasons to improve protein content of maize grain.
The objectives of this study were to:
I. Improve protein content of G-2 maize population.
II. Determine the effect of selection for high protein content on yield grain.
III. Determine the efficiency of full-sib family and half-sib family selection methods.
IV. Selected the best families for protein to constitute experimental varieties.
In 2004 and 2005, families selected for protein from G-2 population were planted at Homs Research Center. Selection methods were full-sib and half-sib family selection with 20% selection intensity each season. Selected progenies for both seasons were tested at three provinces in 2006 (Homs, Aleppo and Raqqa) using simple with two replications) 9— lattice design 9).
The followings are the most important results of this study:
1. Plant height/cm:
Generally, full-sib family selection was better than half-sib family selection method in terms of decrease plant height. The results indicated that improvement of protein content during both cycles affect negatively plant height in the first cycle, but full-sib was low affect in the second cycle.
2. Number of days to flower:
Results showed that no significant difference between full-sib family and half-sib family selection methods. As general mean of tested sites,   Result indicated that improvement of protein content during both cycles did not negatively affect number of days to flower.
3. Leaf area index:
The comparison between full-sib family and half-sib family selection methods showed no significant difference within 1st and 2nd selection cycles all sites.
Result indicated that improvement of protein content during both cycles affect negatively leaf area index in the first cycle. But leaf area index developed for high level F.S and middle level H.S in the second cycle.
4. Grain moisture (%):
At both selection cycles, no significant difference was detected between full-sib family and half-sib family selection methods in terms
of grain moisture with preference for half-sib, either-selected families for protein. The results showed that improvement of protein content during two cycles did not negatively affect grain moisture. This refers to early maturity.
5. Shelling percentage:
The comparison between full-sib family and half-sib family selection methods showed no significant difference within 1st and 2nd selection cycles all sites. The results indicated that improvement of protein content during both cycles did not negatively affect shelling percentage.
6- Weight 1000 Kernels (g):
The comparison between full-sib family and half-sib family selection methods showed no significant difference within 1st and 2nd selection cycles all sites with preference for half-sib in the first cycle, but full-sib was better in the second cycle. The results indicated that improvement of protein content during both cycles affect negatively weight 1000 kernels.
7. Grain yield (ton/ha):
The comparison between full-sib family and half-sib family selection methods showed no significant difference within 1st and 2nd selection cycles all sites.
Result indicated that improvement of protein content during both cycles did not negatively affect shelling percentage with preference for half-sib in the first cycle, but full-sib was better in the second cycle. The full-sib was the best for middle level and high, while half-sib was the best for low level.
Generally, full – sib family was better than half-sib family selection method in terms of grain yield. It may be concluded that improvement of protein content until 11-12% did not negatively affect grain yield, and it recommended for improving G-2 maize population.
8. Protein content (%):
Generally, full – sib family selection was better than half -sib family selection method in terms of protein content, for both selection cycles at all sites for middle level and high, while half-sib was the best for low level. Also, the result indicated that improvement of protein content was effective. Ten families were selected at 2nd compared with 8 families selected at 1st cycle.
9- Protein production (kg/ha):
The comparison between full-sib family and half-sib family selection methods showed no significant difference within 1st and 2nd selection cycles all sites. But full-sib family selection was better than half -sib family selection for middle level and high, while half-sib was the best for low level.
In addition, the results showed that selection for protein production was effective. This result showed that the improvement of protein content did not negatively affect protein production.
10. Oil content (%):
At both selection cycles, full-sib family was better than half -sib family selection in terms of oil improvement at all sites and all levels.
Result indicated that improvement of protein content during both cycles did not negatively affect oil content in the lowest and highest values.
11. Starch content (%):
At both selection cycles, full-sib family was better than half -sib family selection in terms of starch improvement at all sites. The result indicates that improvement of protein content during both cycles affects negatively Starch content in the lowest and highest values.