Trichomes in Segregating Generations of Sorghum Matings. II. Association with Shootfly Resistance¹

Abstract

The shootfly (Atherigona soceata Rond.) is a major seedling pest of sorghum in Asia and Africa. To determine whether the presence of nonglandular trichomes on the leaf lamina was associated with resistance to shootfly, trichomed, segregating, and trichomeless F2-derived lines in the F5 and F, from four trlchomed X trichomeless sorghum matings and their parents were studied at ICRISAT Center, Patancheru, India. Trichomed lines had significantly lower percentages of plants with shootfly eggs 18 days after emergence and of deadhearts (killed central shoot) at both 18 and 23 or more days after emergence. The ratio of the difference between the means of trichomed and trlchomdess lines for the percentage of deadhearts to the corresponding difference between the parents ranged from 0.16 to 0.92 and exceeded 0.32 in seven of nine comparisons. Thus, trichomes were clearly a major factor, but not the only factor, involved in resistance. Means of the parents and trichomed, segregating, and trichomeless offspring were regressed on four possible genetic models. The results indicated that at least two additional loci that interact with each other were involved in resistance. Trichome density was examined as a possible factor in resistance, but correlation of deadheart percentage with the density of trichomes was low and nonsignificant.

Analysis of resistance mechanism to Atherigona soccata in crosses of sorghum

“…This revealed that trichomes on the lower surface is very important and reduces the oviposition. This was in accordance with Blum (1968), Annonymous (1978), Gibson and Maiti (1983) and Maiti and Gibson (1983). On contrary, parent IS 2205 recorded less number of trichomes on the lower surface of the leaf lamina and had much lower numbers of eggs and dead heart per cent than SPSFPR 94004A.…”

Physico-chemical mechanisms of resistance to shoot fly, Atherigona soccata in sorghum, Sorghum bicolor

“…Genotypes with glossy and trichomed leaves are relatively less susceptible to shoot fly damage (Maiti and Gibson 1983; Sharma and Nwanze 1997; Dhillon et al. 2005, 2006b), while leaf surface wetness is associated with susceptibility to shoot fly in sorghum (Nwanze et al.…”

“…The shoot flyresistant genotypes produce more numbers of uniform productive tillers than the susceptible ones, and yield more under shoot fly infestation (Sharma and Nwanze 1997). Genotypes with glossy and trichomed leaves are relatively less susceptible to shoot fly damage (Maiti and Gibson 1983;Sharma and Nwanze 1997;Dhillon et al 2005Dhillon et al , 2006b, while leaf surface wetness is associated with susceptibility to shoot fly in sorghum Dhillon et al 2005). The plumule and leaf sheaths of the shoot fly-resistant genotypes have deeper pink pigment, while the susceptible genotypes were green coloured (Dhillon et al 2006b).…”

Stability of resistance to sorghum shoot fly, Atherigona soccata

“…The genotypes ICSB 425, IS 2312, IS 18662, RSV 1090, RSV 1093, and IS 18551 also showed moderate levels of recovery resistance following shoot fly damage. Oviposition non-preference (antixenosis), antibiosis, and tolerance are the major components of resistance in sorghum to shoot fly (Doggett et al 1970, Raina et al 1981, Sharma and Nwanze 1997, Dhillon et al 2005, 2006a, Kumar et al 2008, and the genotypes having glossy and trichomed leaves are relatively less susceptible to shoot fly damage (Maiti and Bidinger 1979, Maiti and Gibson 1983, Sharma and Nwanze 1997, Dhillon et al 2005, 2006b).…”