Pattern-dependent maternal plastid inheritance in Pennisetum americanum

Abstract

The descendents of the "stripe" mutant of Pennisetum americanum consisted of green, variegated, and yellow seedlings. Variegation pattern differed from plant to plant, from tiller to tiller within a plant, and from leaf to leaf on the same tiller. The chlorophyll content (A₆₆₃ per square decimetre) also differed among the variegated plants and leaves. The progeny from each of the variegated plants consisted of green, yellow, and variegated seedlings in varying proportions. In general, more green progeny were recovered from plants with wider green sectors in their top two leaves and more yellow seedlings were recovered from plants with top leaves showing wider yellow sectors. However, variegated seedlings were predominant among the progeny of plants exhibiting a greater number of interspersions of green and yellow stripes, irrespective of the total area of each colour. The variations in the proportions of different progeny are dependent upon the variegation pattern and the chlorophyll content of the top two leaves. The production of exclusively yellow seedlings from yellow spikelets irrespective of pollen source and the reciprocal differences in the interspikelet crosses suggest maternal plastid inheritance. Thus, the breeding behaviour of the variegated plants and the results of interspikelet crosses indicate a pattern-dependent maternal plastid inheritance.