Inheritance of Resistance to Ergot Disease in a Diallel Cross of Pearl Millet (Pennisetum glaucum (L.) R. Br.)

Abstract

field study was conducted to incorporate resistance to ergot and determine its inheritance in four pearl millet hybrids (SOSAT C88, Ex-Borno, LCIC 7902 and PEO 5948) from three resistant local pearl millet landraces (Geron Tsuntsu, Zango and Dandigali). Crosses of the seven pearl millet lines were carried out in all possible combinations but without reciprocals using diallel mating design to generate 21 F1 populations during the 2011 dry season to March 2012 under irrigation system at the University of Maiduguri Teaching and Research Farm, Nigeria. The seven parental lines and 21 F1 hybrids were evaluated for ergot disease, days to 50% flowering and grain yield in a randomized complete block design (RCBD) with three replications during the 2012 rainy season in Gombe, Nigeria. Results showed that each of the seven parent lines attained 50% flowering at statistically similar days with their respective crosses except for SOSAT C88 (SOSAT C88 vs Dandigali and LCIC 9702), Zango (Zango vs SOSAT C88, LCIC 9702 and Dandigali) and PEO 5948 x LCIC 9702. This synchrony provided a uniform condition and duration for evaluating the resistance to ergot infection in the crosses vis-à-vis the parent cultivars. F1 between either SOSAT C88, Ex-Borno or LCIC 7902 and each of landrace cultivars showed positive heterosis for ergot disease. Zango x Dandigali and Geron Tsuntsu x PEO 5948 showed the lowest incidence (15.00%, 16.67% respectively) while SOSAT C88 and SOSAT C88 x Ex-Borno gave the highest (50.00%, 45.00% respectively). Lowest ergot severity was recorded from F1 between Dandigali and either Ex-Borno (6.17%) or Geron Tsuntsu (6.33%) although not significantly (p=0.05) different from Geron Tsuntsu x PEO 5948 (08.08%) while SOSAT C88 and LCIC 9702 had the highest severity (31.61%, 33.25% respectively). SOSAT C88 x Zango gave significantly the highest grain yield (391.81 kg/ha) while SOSAT C88 recorded the lowest grain yield (101.11 kg/ha). The results of the study showed that the local landraces of pearl millet used in the study have genetic potential to manage ergot disease in hybrids of pearl millet due to their ability to confer resistance and desirable heterosis for disease and yield in their F1. Multi-locational trials need to be conducted on the crosses that showed resistance to ergot to confirm the stability and durability of their resistance.

Keywords: Claviceps fusiformis, diallel mating design, incidence, pearl millet, severity.