S. Appa Rao

New sources of dwarfing genes in pearl millet (Pennisetum americanum).

SummaryThirteen naturally occurring dwarf lines of pearl millet [Pennisetum americanum (L.) Leeke], identified from the world collection, varied for several morphological and agronomic characters. Extreme dwarfs were characterized by a tufted growth habit which could be distinguished from the time of germination, while the other dwarf lines could be distinguished only after anthesis. The F1 hybrids between the tall and dwarf genotypes were tall, indicating that dwarfness is a recessive trait. In 10 out of the 13 crosses, the F2 segregation ratio was three tall to one dwarf (3∶1) suggesting that the dwarfness is controlled by a single recessive gene, while the height differences in 3 of the dwarfs (IP 8056, IP 8210 and IP 8214) were controlled by more than one gene as they showed continuous variation for plant height in F2. When the remaining 10 single gene dwarfs were crossed to either d1 (‘Tift 238’) or d2 (‘Tift 23 DB’) dwarfs, only 2 crosses produced tall F2 hybrids and they segregated for height in F2 indicating that these 2 dwarfs are non-allelic to d1 and d2. Reciprocal crosses of these 2 dwarfs produced tall F1 hybrids and showed a dihybrid segregation of 9∶3∶4 in F2 indicating that the dwarfing genes of these 2 parents are non-allelic to each other. These non-allelic dwarfs were assigned the gene symbols d3 (IP 10401), and d4 (IP 10402).

Collection and evaluation of pearl millet (Pennisetum americanum) germplasm from Ghana

An expedition to Ghana was undertaken during August 1981 to collect mainly the early-maturing pearl millet, Pennisetum americanum. The collection team travelled extensively in most of the pearl millet-growing areas of the eastern and northern provinces of Ghana. The mission was planned to coincide with harvesting so that early-maturing landraces could be obtained from farmers’ fields. Seed samples of late-maturing pearl millet were also obtained from local markets. Early-maturing pearl millet is traditionally intercropped with groundnut (Arachis hypogaea), sorghum (Sorghum bicolor) or late-maturing pearl millet. Pearl millet grain is used in several traditional food preparations: thick porridge called tô, a thin, fermented porridge calledkoko, and a deep-fried pancake calledmarsa. Landrace populations grown by the farmers were mixtures of several types. The material collected varied considerably for shapes, sizes and colors of spikes and grains. Of the 284 samples collected, 227 were grown in a uniform nursery at Patancheru: they flowered in 39–140 days, grew 120–315 cm tall, spikes were short (6–53 cm) and conical, grains were large, globular and gray with starchy endosperm. The samples belong to race globosum and serve as a good source of genes for earliness and large-grain size.

Germinability and seedling vigor of pearl millet seeds harvested at different stages of maturity

Abstract The effect of seed maturity on germinability and seedling vigor was studied in four cytoplasmic male sterile lines of pearl millet (Pennisetum glaucum (L.) R. Br.). The male sterile plants were crossed with pollen from respective maintainer lines, and developing seeds at different stages of maturity were harvested. Fresh weight of seeds increased gradually to a maximum in 28–35 days and then decreased. Maximum dry-matter accumulation in grain occurred at 28–35 days after pollination when the average moisture content was 22.7%. Seeds of some lines harvested at 10 days after pollination germinated, but the highest percentage germination was observed at 35 days in all lines. The maximum mean seedling vigor occurred at 35 days and coincided with the maximum dry weight of the seeds. Germplasm collectors can collect germinable seeds much earlier than the time of accumulation of maximum dry matter. However, for conservation, it is desirable to store mature seeds with maximum germination and vigor.

Identification, characterization and geographic distribution of male-sterility restorer and maintainer lines from diverse pearl millet germplasm

SummaryTo determine the distribution and geographic specificity of sterility maintainers in pearl millet, Pennisetum americanum (L.) Leeke, 428 diverse pearl millet germplasm accessions representing variation from 12 countries were crossed with a male-sterile line 5141A. The F1 hybrids were classified as male-fertile or male-sterile based on the seed set on bagged ear heads and an other morphology. Among these, 87 (20.3%) were classified as male-fertile, 32 (7.5%) as male-sterile, 282 (65.9%) as segregating for male-fertile/male-sterile and 27 (6.3%) behaved as male-fertile in the rainy and male-sterile in the postrainy season. Restorer lines were distributed in all the countries studied except Cameroon and USSR. Maintainer lines were observed from six countries but were concentrated in India. These maintainer lines differ from one another in several morphological and agronomic characters such as flowering, plant height, spike length and grain size. They may prove to be useful sources of material for generating new male-sterile lines. The restorers can be used to produce commercial hybrids.