Rao, N.G.P. (1970) Genetic Analysis of Some Exotic X Indian Crosses in Sorghum. 1. Heterosis and its Interaction with Seasons. Indian Journal of Genetics and Plant Breeding, 30 (2). pp. 347-361.
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Abstract
When msCK60 was used as the common female parent, the improved indigenous sorghum varieties used as pollinator parents inspite of their adaptability to some agroclimatic regions of India, did not result in hybrids of commercial value. This could be attributed mainly due to lack of heterosis in kharif season, an undesirable plant type and difficulties in threshability. During the rabi season, in spite of limited heterosis with both exotic and Indian parents, greater susceptibility of hybrids to shoot-fly and relatively inferior grain quality compared to the local rabi varieties did not enable the development of any commercial hybrid for this season. The first hybrids released for kharif and summer seasons were, therefore, exotic X exotic combinations. An examination of the heterotic response of the components of yield revealed that heterosis was generally negative for the length of the secondary branches and the number of tertiary branches. Considering panicle morphology, the emphasis in compact headed Indian varieties is on girth which is due to relatively longer secondary branches with more number of tertiaries, while in exotics panicle length was generally pronounced. When such varieties were combined, there seems to be lack of reinforcement between genes or gene complexes for length of primary axis and those contributing to girth, resulting in limited or no heterosis for ultimate yield. Heterosis for panicle components seems to be maximum for characters evolved in the same direction irrespective of their geographic origin. The estimates of the components of variance for parents and hybrids reveal that hybrids are more stable than parents during kharif season. During the rabi season the magnitude of such estimate is as large for hybrids as for males indicating that heterozygosity is not necessarily related to stability. The number of secondary branches is the least stable character, whereas the length of the secondary branches and the number of tertiaries are most stable. These stable characters are observed to be least heterotic. The limitations imposed by the genotype-environment (season) interactions on the magnitude of heterosis are well brought out. In spite of the common female parent msCK60 being a non-interactor in both seasons, the hybrids behaved differently. While the exotic X exotic combinations were most heterotic in the kharif environment, genotype-environment interactions acted in a direction opposite to that of heterosis resulting in limited heterosis during rabi. It, therefore, appears necessary at least in the immediate future to develop different groups of hybrids for kharif and rabi seasons. Development of parental stocks which are stable for the number of secondary branches in both seasons may enable development of commercial hybrids common for both the seasons.
| Item Type: | Article |
|---|---|
| Author Affiliation: | All India Coordinated Sorghum Improvement Project, I.A.R.I. Regional Research Station, Hyderabad-30, A.P. |
| Subjects: | Statistics and Experimentation Crop Improvement |
| Divisions: | Sorghum |
| Depositing User: | Mr. SanatKumar Behera |
| Date Deposited: | 29 May 2012 04:11 |
| Last Modified: | 29 May 2012 04:11 |
| Official URL: | http://www.indianjournals.com/ijor.aspx?target=ijo... |
| URI: | http://eprints.icrisat.ac.in/id/eprint/5865 |
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