HETEROSIS AND COMBINING ABILITY IN RELATION TO CYTOPLASMIC DIVERSITY IN PEARL MILLET

Abstract

In pearl millet (Pennisetum glaucum) several sources of cytoplasmic male-sterility (CMS) are available. This investigation was undertaken to study the combining ability of alloplasmic isonuclear lines and to quantify the magnitude of heterosis in hybrids based on different CMS sources. Such information is ultimately helpful in determining the relative chances of success with any CMS source. The lines with A3 and A4 cytoplasms were significantly better general combiner for grain yield than the lines retaining either Al male-sterile or fertile cytoplasm. Pollinators IPC 1173, IPC 1600, IPC 1546 and IPC 390 proved their utility for breeding high yielding hybrids. None of the pollinateitS proved to be good combiner simultaneously for all traits. Magnitude of heterosis varied considerably within the hybrids retaining particular cytoplasm. Heterosis was negative for days to flower and of the similar magnitude in the hybrids grouped by their cytoplasmic source. Manifestation of cytoplasmic effects was higher for heterosis for grain yield and plant height than heterosis for days to flower and panicle length. The usefulness of A4 CMS source is discussed, in the light of results obtained here and those already available, in pearl millet hybrid breeding programmes.