Flowering events in sorghum in relation to expression of resistance to sorghum midge, Stenodiplosis sorghicola

Sharma, H.C. and Hariprasad, K.V. (2002) Flowering events in sorghum in relation to expression of resistance to sorghum midge, Stenodiplosis sorghicola. Euphytica, 127 (3). pp. 411-419.

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Sorghum midge (S. sorghicola) is an important pest of grain sorghum, and host plant resistance is one of the most effective means of controlling this pest. Several studies have shown that resistance to sorghum midge is associated with short and tight glumes, faster rate of grain development and tannins. However, some recent studies suggested that time of flowering is the principal component of resistance to sorghum midge. Therefore, we conducted a series of experiments under laboratory and field conditions (Andhra Pradesh, India) on the flowering behaviour of a diverse array of midge-resistant and midge-susceptible genotypes to quantify the contribution of time of flowering in genotypic resistance to sorghum midge. Time of flowering under field and laboratory conditions did not show any differences between midge-resistant and midge-susceptible genotypes. Time to maximum flowering varied considerably between the rainy and the post-rainy seasons. Under field conditions, most of the spikelets in the midge-resistant lines opened between 00.00 and 04.00 h, while most of the spikelets in the susceptible control, CSH 1, opened at 02.00 h. Under light and dark conditions in the laboratory, most of the spikelets opened at 03.00 h in all genotypes, irrespective of their level of resistance to the sorghum midge. However, flowering events continued for a longer period under dark conditions outside the laboratory. There were no differences in oviposition in panicles on the midge-resistant genotype, ICSV 745, infested between 02.00 and 06.00 h, and significantly more eggs were laid in spikelets of the susceptible control, CSH 1, than in the midge-resistant, ICSV 745, at all infestation times. The peak oviposition was recorded at 09.45 h irrespective of the level of resistance to sorghum midge, and significantly more eggs were laid in the spikelets of CSH 1 and Swarna than in ICSV 745 and ICSV 197. There was no evidence of change in the susceptibility of sorghum midge-resistant genotypes when infested at different times in relation to time of flowering. Therefore, flowering behaviour of sorghum genotypes seems to play little role in genotypic susceptibility to sorghum midge

Item Type: Article
Author Affiliation: International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru 502 324 Andhra Pradesh, India
Subjects: Plant Protection > Pesticides
Plant Protection > Pests
Crop Improvement
Divisions: Sorghum
Depositing User: Mr B Krishnamurthy
Date Deposited: 20 Apr 2011 04:58
Last Modified: 20 Apr 2011 04:58
Official URL: http://dx.doi.org/10.1023/A:1020387322539
URI: http://eprints.icrisat.ac.in/id/eprint/1825

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