Performance stability of maize genotypes across diverse hill environments in Nepal

The national maize improvement program in Nepal regularly receives elite maize (Zea mays L.) genotypes from CIMMYT and other countries and tests them for their performance stability in highly diverse environments. Studies were conducted on research stations and farmers’ fields at five sites in three years to determine performance stability of exotic maize genotypes. Replicated on-station and on-farm studies were conducted using 25 and 10 genotypes, respectively, including a local check and an improved check (Manakamana-3), in 2004–2006. We analyzed grain yield, days to flowering, plant and ear height, plant population, husk cover, and plant and ear aspect. Stability and genotype superiority for grain yield was determined using genotype and genotype × environment (GGE) biplot analysis that compares among a set of genotypes with a reference ‘ideal’ genotype, which has the highest average value of all genotypes and is absolutely stable. Several genotypes produced significantly higher grain yield than the local check. Four genotypes (‘Across9942 × Across9944’, ‘Open Ended White Hill Population’, ‘Population 44C10’ and ‘ZM621’), that produced significantly higher grain yield than the improved check, also had other agronomic traits (days to flowering, plant and ear height, number of ears, resistance to leaf blight, plant and ear aspect and husk cover tightness) equal to or better than the improved check. GGE-biplot analysis showed that Across9942 × Across9944 and ZM621 were the most superior genotypes in the on-station and on-farm trials, respectively. The findings from this study provide new information on the stability of the maize genotypes that are also adapted to other regions of the world. Such information could be useful for maize improvement program for the highlands in Nepal and other similar environments.     

Mycobiotic Flora of Female Genitalia of Buffaloes and Cows with Reproductive Disorders

Veterinary Research Communications -     

Molecular markers and their applications in wheat breeding

In recent years, considerable emphasis has been placed on the development of molecular markers to be used for a variety of objectives. This review attempts to give an account of different molecular markers—restriction fragment length polymorphisms (RFLPs), random amplified polymorphic DNAs (RAPDs), sequence-tagged sites (STS), DNA amplification fingerprinting (DAF), amplified fragment length polymorphisms (AFLPs) and microsatellites (STMS)—currently available for genome mapping and for tagging different traits in wheat. Other markers, including microsatellite-primed polymerase chain reaction (MP-PCR), expressed sequence tags (ESTs) and single nucleotide polymorphisms (SNPs) are also discussed. Recent information on synteny in cereal genomes, marker-assisted selection, marker validation and their relevance to cereal breeding in general and wheat breeding in particular are also examined.     

Biomass production of trees and grasses in a silvopasture system on marginal lands of Doon Valley of north-west India 2. Performance of grass species

In a long-term study (1980 to 1993), the survival, growth performance and biomass production of two grass species viz. Chrysopogon fulvus (Spreng.) Chiov. and Eulaliopsis binata (Retz.) C.E. Hubb. were assessed when intercropped with four tree species viz. Albizia lebbek (L.) Benth., Grewia optiva Drumm., Bauhinia purpurea L. and Leucaena leucocephala (Lamk.) de Wit. on the bouldery riverbed lands of Doon Valley of north-west India. The survival of grass clumps was higher under the canopy of B. purpurea (48.3% in 1993 of the initial planting density of 20,000 clumps ha⁻¹ in 1980) and G. optiva (47.4%) than of L. leucocephala (31.1%) and A. lebbek (29.4%), and at 75% intensity of tree lopping (40.9%) than at 50% (37.1%). The effect of tree species on different growth parameters of grasses was not uniform, with G. optiva and B. purpurea causing comparatively more synergistic effect on clump height and clump diameter respectively. Although the performance of grasses was good under A. lebbek and L. leucocephala in the early years (1980--1987), these tree species resulted in the lowest grass dry weight in the later years up to 1993. The beneficial effect of higher lopping intensity of 75% was observed on the growth and biomass production of grasses over 50% lopping, presumably due to increased light penetration into the under-storey. The biomass production of grasses reached a maximum at four years of growth in 1983, after which, it decreased gradually to less than half in 1993. Eulaliopsis binata showed higher survival, growth and biomass production than C. fulvus throughout the period of study. The total biomass production was highest in association with B. purpurea followed by G. optiva, which appeared to be the most suitable tree species along with E. binata for sustainable silvopasture development on the marginal lands of Doon Valley of north-west India. This revised version was published online in June 2006 with corrections to the Cover Date.     

Isolation of arbuscular mycorrhizal fungi and Azotobacter chroococcum from local litchi orchards and evaluation of their activity in the air-layers system

Soil samples were collected from rhizosphere of litchi-growing areas of North-Western Himalayan Region (NWHR) of India, for finding qualitative and quantitative differences in arbuscular mycorrhizal (AM) fungi and Azotobacter chroococcum. These samples were taken from plants being grown in different cultivation types namely, weed control with weedicides or tillage; orchard floor either clear or with cover crops; intercropping with cereals and legumes. Qualitative and quantitative differences were noticed with different cultivation types and a marked reduction in the AM fungi was observed in orchards where chemicals were used for weed control and intensive farming system was used on the orchard floor. AM fungi were generally abundant in the soils with range pH 5.5–6.6. Among different AM fungi retrieved from the soils, Glomus spp. was most dominant. Fifteen AM fungal species were isolated, identified and characterized and along with their ability to colonize the roots. In the soil samples, a marked variation in viable bacterial count of A. chroococcum was also noticed due to varied physico-chemical characteristics of the orchard soils. The changes in AM fungal species composition can be attributed to changes in soil chemical properties resulting from cultural practices such as ploughing, application of chemical fertilizers and weedicides. An experiment was also conducted to study the comparative efficacy of four dominant and frequently occurring indigenous AM species namely, Glomus fasciculatum (Thaxter sensu Gerdemann), G. magnicaulis (Hall), G. mosseae (Nicol. & Gerd.), Gigaspora heterogamma (Nicol. & Gerd.) and two A. chroococcum strains viz., AZ₁ and AZ₂ singly and in dual combination to evaluate their effect in air-layers system. Dual inoculation of G. fasciculatum and AZ₁ increased total root length of air-layered shoots by 81.39% over uninoculated control. These studies indicated that indigenously isolated AM fungal species and A. chroococcum strains can be used for air-layering for better adaptation under specific agro-climatic and ecological zone conditions.     

Screening of vincristine yield in ex vitro and in vitro somatic embryos derived plantlets of Catharanthus roseus L. (G) Don.

Catharanthus roseus L. (G.) Don. (Apocynaceae) is an important dicotyledonous medicinal plant as it is the sole source of vincristine and vinblastine that are used against a variety of cancers. Quantitative estimation of vincristine was carried out using high performance liquid chromatography (HPLC) in various in vitro grown tissues; calluses (embryogenic and non-embryogenic callus), embryogenic stages (proliferated, matured and germinated embryos), somatic embryo derived plantlets (leaf, root and whole plant) and leaves of ex vitro developed plantlets. The yield in those in vitro and ex vitro-developed tissues was monitored for 30 weeks. Except at an early lag period, vincristine production was detected up to 20–25 weeks old plant samples. Vincristine content was very high in leaf callus and germinated embryos. Leaves of in vitro raised plants showed higher amount of vincristine when compared to ex vitro-developed leaves of similar age. Vincristine production was tissue specific and age dependent that was discussed in detail in this present communication.     

Heterosis for mineral elements in single cross-hybrids of cabbage (Brassica oleracea var. capitata L.)

Cabbage (Brassica oleracea var. capitata L.), a cross-pollinated crop, was observed to exhibit strong heterosis for high yield; better plant stand; early maturity; larger and more uniform heads; uniformity in head compactness; and disease tolerance in F₁ hybrids. However, information on the heterosis for mineral elements such as Fe, Zn, Cu, Mn, K and Ca although is not available to the best of our knowledge but it is important as it is likely to influence the plant and subsequently the human nutrition. Therefore, an attempt was made to estimate the heterosis for mineral elements in cabbage. Significant mean square for parents and hybrids was observed for all minerals under study which indicated the prevalence of sufficient variation. The parents 83-2, Pride of Asia, Red Cabbage, AC-204 and MR-1 were found to have the potential for use in cabbage quality breeding programme as they exhibited higher hybrid effects for Fe, Zn, Cu and Mn content. The single cross-hybrids, i.e. 83-2 × AC-204; Pride of Asia × C-2 and Pride of Asia × Red Cabbage; Pride of Asia × MR-1; 83-2 × Red Cabbage; and Pride of Asia × AC-204 and 83-2 × MR-1 were the best for Fe and Zn; Fe and Cu; Zn and Mn; Cu and Zn; and Cu, respectively. This study revealed clearly that none of the hybrids excelled for all the minerals suggesting the significance and need for multiple crossing breeding approaches, i.e. three way cross-hybrid, double cross-hybrid, population improvement, synthetics, composites, etc., for increasing the mineral concentration in cabbage head, i.e. “Breeding Cabbage for Higher Mineral” (Biofortification) without losing the vigour advantage for yield and other traits of economic importance to combat mineral deficiencies in human beings and plant systems.     

Antigens of Goat Spermatozoa that Recognize Homologous Zona Pellucida

Goat sperm surface proteins obtained from purified plasma membrane (PPM) vesicles (purity of membrane checked by marker enzymes and transmission electron microscopy) were size fractionated on an fast protein liquid chromatography (FPLC) gel filtration column. All the seven surface proteins (129, 100, 46, 28, 27, 18 and 10 kDa) obtained were further fractionated and purified on high-efficiency gel filtration (GFC-HPLC) as well as ion exchange (DEAE-HPLC) columns. Antibodies were generated against the PPM and the protein fractions. Such resolved and purified surface antigens were tested by Dot Blot Immunoassay and homologous in vitro sperm-zona binding assays. It was revealed that the binding of goat spermatozoa to homologous zona pellucida was inhibited by antisera raised against the five lower molecular weight surface antigens. Further, the components of FPLC-AIII (46 kDa; A represents antigenic protein) and IV (28 kDa) were most promising as the antibodies against these fractions inhibited sperm binding to zona pellucida even at a dilution of 1 : 1000 as tested by the sperm-zona binding assays.     

Effect of thiourea on the histopathology and the reproductive performance of the male flesh fly Sarcophaga ruficornis (Fabr.)

When newly emerged and 24-hour-old male flesh flies Sarcophaga ruficornis (Fabr.) were fed on food containing 1.5% thiourea for 24 h, there was a small decrease in the size of the testes in both cases. Disturbance in spermatogenesis and histopathological damage were also observed in both cases. However, in the newly emerged flies the effect was mainly on secondary spermatocytes and spermatids, while in the others the effect was more pronounced on spermatogonia. The reproductive performance in respect of the production of larvae was considerably diminished in the newly emerged treated flies and was even further diminished in flies that were 24 h old when treated. The rate of adult emergence, however, remained unaffected for both kinds.     

Origin and cytology of a novel cytotype of Allium tuberosum Rottl. ex Spreng. (2n = 48)

Naturally occurring/spontaneously produced polyploids with six/more genomes are rarely found in Alliums. A hexaploid form of Allium tuberosum with 2n = 48 chromosomes has been isolated for the first time amongst the open-pollinated seedlings of a hypotetraploid plant (2n = 4x = 31); latter being the seed-derived product of a normal tetraploid stock (2n = 4x = 32) growing in Jammu University Botanical Garden. Except for the guard cells and pollen grains that are of increased size, this form compared to its progenitor is dwarf, has smaller leaves and bears inflorescences with few flowers. This plant is also different from its progenitor in having nearly one-fourth (27.8 %) of its pollen mother cells (PMCs) with varying chromosome number viz. 27–64, with the remaining cells having somatic or double the somatic number of chromosomes. To assess the nature of hexaploid form, its chromosomes were studied for morphological details, putative grouping and pairing properties during reduction division. Morphological similarity in the chromosomes of the present cytotype and its progenitor, arrangement of 48 chromosomes in eight groups of six chromosomes each and presence of 21.88 % euploid cells with eight hexavalents pointed towards the autopolyploid nature of the present strain. Regarding the origin of this strain, observation made on the meiosis in the two sex mother cells of the progenitor provides some clues. In the later plant, presence of most of embryo-sac mother cells with 62 chromosomes that showed 31:31 segregations and existence of majority of the PMCs with 31 chromosomes exhibiting erratic segregations indicate that the hexaploid strain has probably originated as a result of the fusion of reduced male (n = 17) and unreduced female gamete (2n = 31).