DIMENTIONS OF SCC THEORY IN A MAIZE HYBRID-INBRED COMPARISON

M. Elsahookie, Medhat

	DIMENTIONS OF SCC THEORY IN A MAIZE HYBRID-INBRED COMPARISON
The Iraqi Journal of Agricultural Science
Article 1, Volume 38, Issue 1, 2007, Pages 128-137
Author
Medhat M. Elsahookie
Abstract
Two inbreds (CA,2 & B73) of 2 ears/plant of maize were planted and crossed in spring season of 2006. This was to compare some growth parameters thought to be related to SCC (system capacity constant). Data were recorded on some growth parameters, genetic-morphologic and genetic-physiologic components. The results obtained revealed that hybrid vigor had increased SCC of the hybrid via gene action influenced some plant traits. The most prominent parameters found to affect SCC was crop growth rate (CGR). It was 5.5 and 3.9 g/plant Id for hybrid and inbred, respectively. This caused hybrid plants to reach silking faster than its faster parent (58 & 66d). This was reflected on the earliness of metabolites transported from source to sink in the hybrid. Beside that, the period between silking of the two ears of the hybrid was 1-3 d , while in the inbred it was 5-9 d . That was the cause to produce two similar ears in weight of the hybrid, whereas, they were greatly different in the inbreds. Plants of the hybrid produced 923 kernels while of the inbreds, the average was 634 only. High CGR in the hybrid plant had the major effect in increasing the source (TDM). The plant TDM was 654 g in the hybrid and 469 g in the inbred. However, hybrid vigor did not reveal any remarkable increase in neither ears /plant nor rows/ear. It was 1.4 & 1.3 ear/plant and 15.8 & 15.5 row/ear to the hybrid and inbred, respectively. There were four clear dimensions for SCC; I-CGR, 2- TDM 3- Earliness of silking which lengthened seed filling duration, then increased seed weight (0.33 g & 0.27 g/k for hybrid & inbred), 4- High% of metabolites transported to sink to increase number of kernel/ear, and then harvest index (46% & 37% for hybrid & inbred). Accordingly, it was expected that selection for these parameters to breed inbreds will help to develop elite hybrids of higher productivity than hybrids grown to day.

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