M. H. Mengesha

Phylogenetic relations in section Arachis based on seed protein profile

SummarySeed protein profiles of nine diploid species (2n = 20), ten tetraploid accessions, two synthetic amphidiploids and two autotetraploids (2n = 40) were studied using SDS-polyacrylamide gel electrophoresis. While the general profiles suggested considerable homology among these taxa in spite of speciation and ploidy differences, appreciable genetic differences were present to support the existing genomic divisions and sub-divisions in the section Arachis. A high degree of relationship was indicated between the two diploid species (A. duranensis containing the A genome and A. batizocoi (ICG 8210) containing the B genome) and tetraploids A. monticola/ A. hypogaea (2n = 40) containing AABB genome. Similar relationships were recorded between the AABB synthetic amphidiploid and the profile obtained from the mixture of protein of A. duranensis and A. batizocoi, suggesting that these two diploid species were the donors of the A and B genome, respectively, to tetraploid A. monticola/A. hypogaea.

Morphological diversity in sorghum germplasm from India

SummaryOf the 5000 sorghum (Sorghum bicolor L. Monench) germplasm accessions assembled at ICRISAT Asia Center (IAC), over 4000 accessions from 11 major sorghum growing states in India were evaluated for morphological and agronomical characters at IAC during rainy and postrainy seasons.Considerable diversity was observed for all the characters studied. Diversity was more among states than within states. Variation among the seasons was also considerable. Days to flowering ranged from 42 to 129 days during postrainy and 33 to 180 days during the rainy season indicating their day length sensitivity. Plant height ranged from 65 to 330 cm during postrainy and 75 to 655 cm during rainy season. Panicle length ranged from 5 cm to 52 cm and panicle width from 1 to 51 cm. Erect and compact panicles are more frequent although all possible panicle shapes and compactness were found. In general, sorghums from India produce medium to large, lustrous grains in which the subcoat (testa) is absent. All the 5 basic and 10 intermediate sorghum races were found in India though durra or half-durra predominate. Racial diversity is maximal in the state of Andhra Pradesh followed by Maharashatra state. In the world collection a majority of the sources of resistance to shoot fly, stem borer, and striga are from India. Based on diversity for morphological and agronomical characters, India could be considered as the secondary center of diversity. Sorghum germplasm from India is useful for good quality large grain.

Cross compatibility between chickpea and its wild relative, Cicer echinospermum Davis

SummaryCicer echinospermum, a wild relative of chickpea (Cicer arietinum L.), has traits that can be used to improve the cultivated species. It is possible to obtain successful crosses between the two species, even though their cross progenies have reduced fertility. The reasons for this low fertility could be due to the two species differing in small chromosome segments or at genic level. Another limitation to the use ofC. echinospermum at ICRISAT Asia Center is that the species is not adapted to the short photoperiod which prevails during the chickpea cropping season at Patancheru, Andhra Pradesh, India. Future work will include screening the segregating progenies for monitoring traits from both the species through isozyme analysis and to incorporate these into good agronomic backgrounds following backcrosses.

Leaf types and their genetics in chickpea (Cicer arietinum L.).

SummaryCommonly the chickpea leaf is uni-imparipinnate, having 9–15 leaflets. However, certain variants have been reported; these are available in the chickpea collection at ICRISAT and were re-examined. Based on the lamina differentiation, three major classes of leaf type can be recognized: uni-imparipinnate (normal), multipinnate and simple (leaf). (Certain other leaf forms reported earlier are not classes of leaf type though they are distinct variants). It was determined that the leaf type differences are governed by two genes (mlsl), which show supplementary gene action. The multipinnate leaf is formed when the first gene is dominant (ml+sl/.sl). Whereas the simple leaf occurs when the first gene is recessive and the second gene is in either form (ml./ml.), the normal leaf is expressed when both dominant genes are present (ml+sl+/..).

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).

Morphology and cytology of Cicer canariense, a wild relative of chickpea'

SummaryThe short note describes the morphology and chromosome number of Cicer canariense Santos Guerra & Lewis. This taxon has been found to have a meiotic chromosome number of 2n<16 and not 2n<24, as reported earlier. At ICRISAT Center, while other perennial Cicers did not perform well, Cicer canariense flowered and produced seeds. The species grew vigorously and had multi-podded peduncles and multi-seeded pods. Such traits of Cicer canariense can be very useful in the genetic improvement of chickpeas.

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.