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  • Drosophila ananassae  (4)
  • Calcareous soil  (3)
  • Rice  (3)
  • Vigna unguiculata  (3)
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Keywords
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 69 (1985), S. 437-441 
    ISSN: 1432-2242
    Keywords: Inversion karyotypes ; Relative fitness ; Heterosis in interpopulation crosses ; Coadaptation ; Drosophila ananassae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The relative viabilities of homozygous and heterozygous karyotypes were measured by making crosses between strains ofD. ananassae homozygous for ST or inverted gene orders in the second and third chromosomes. The strains utilized during the present study originated from widely separated localities in India, Kuala Lumpur and Kota Kinabaru, Malaysia and Chian Mai, Thailand. The presence of heterosis in many interpopulation crosses is evident from the results which show that the inversion heterozygotes formed by chromosomes coming from distant populations exhibit heterosis. On the other hand, heterosis is absent in two intrapopulation crosses. Thus the present results provide evidence that heterozygosis for many genes and gene complexes does produce high fitness without previous selectional coadaptation.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-5036
    Keywords: Calcareous soil ; Modified-urea materials ; Oryza sativa L. ; Rainfed lowland ; Zinc deficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Studies revealed that Zn-deficiency symptoms were induced markedly by the levels of nitrogen and its source in rainfed lowland rice grown on calcareous soil. Visual Zn-deficiency symptoms recorded 3 weeks after transplanting showed that increased supply of nitrogen at puddling resulted in significant increase in the extent of deficiency symptoms of this nutrient element. Zn-deficiency symptoms got aggravated with Mussorrie Rock Phos-coated urea (MRPCU) followed by sulphur-coated urea (SCU). Zn-deficiency symptoms induced by urea supergranules (USG) and prilled urea (PU) supplying two-thirds of nitrogen as basal were found to be of moderate level. No symptoms of Zn-deficiency were noted with no-nitrogen control.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1573-5036
    Keywords: Calcareous soil ; DTPA-extractable iron ; Iron ; Lentil ; Rice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary In a pot experiment with 26 calcareous soils, the critical limit of Fe in soils and plants was evaluated. DTPA-extractable Fe was found significanty correlated with Bray's per cent yield in rice. The Fe2+ (iron) in rice and lentil was also found significantly correlated with DTPA-extractable Fe as well as Bray's per cent yield showing thereby the superiority of Fe2+ (iron) in leaves over DTPA-extractable soil Fe to differentiate Fe responsive soils from non-responsive ones. The total Fe content in plant tissues does not seem correlated with the occurrence of Fe deficiency. The threshold values of DTPA-extractable soil Fe and Fe2+ (iron) in rice and lentil leaves were 6.95, 44 and 74.5 ppm, respectively below which appreciable responses to Fe application were observed. The optimum Fe level for these soils was found to be 10 ppm in which the dry matter yield response in all the 19 rice soils and 16 lentil soils ranged from 14.28 to 56.16 (Av. 25.75%) and 13.31 to 53.97 (Av. 22.47%), respectively.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Genetica 97 (1996), S. 321-329 
    ISSN: 1573-6857
    Keywords: Drosophila ananassae ; population and behaviour genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Drosophila ananassae is a cosmopolitan and domestic species. It occupies a nuique status among the Drosophila species due to certain peculiarities in its genetic behaviour. The most unusual feature of this species is spontaneous male recombination in appreciable frequency. The present review summarises the work done on population and behaviour genetics of D. ananassae from India. Population dynamics of three cosmopolitan inversions has been studied in Indian population of D. ananassae and it is evident from the results that there is a considerable degree of genetic divergence at the level of inversion polymorphism. In general, the populations from south India show more differentiation than those from the north. These three cosmopolitan inversions, which are coextensive with the species, exhibit heterosis. Interracial hybridization does not lead to beaakdown of heterosis, which suggests that evidence for coadaptation is lacking in geographic populations of D. ananassae. Heterosis appears to be simple luxuriance rather than populational heterosis (coadaptation). Unlinked inversions occur in random associations, indicating no interchromosomal interactions. However, two inversions of the third chromosome often show strong linkage disequilibrium in laboratory populations, which is due to epistatic gene interaction and suppression of crossing-over. Genetic variations for certain allozyme polymorphism and sternoleural bristle phenotypes in Indian populations of D. ananassae have also been observed. A number of investigations have also been carried out on certain aspects of behaviour genetics of Indian D. ananassae. There is evidence for sexual isolation within D. ananassae. Significant variations in mating propensity of several isofemale strains, inversion karyotypes, the diminishing effects of certain mutations on sexual activity of males and positive response to selection for high and low mating propensity provide evidence for genetic control of sexual behaviour in D. ananassae. Males contribute more to variation and thus are more subject to intra-sexual selection than females. Evidence for rare male mating advantage has also been presented. Geographic strains of D. ananassae show variation with respect to oviposition site preference. The results of studies on pupation site preference, which is an important component of larval behaviour, suggest that larval pupation behaviour in D. ananassae is under polygenic control with a substantial amount of additive genetic variation.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1573-5060
    Keywords: Vigna unguiculata ; cowpea ; early generation selection ; single seed descent selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Two breeding procedures were compared in two cowpea crosses. Both procedures were started from the same selected F2 plants in each cross. For the early generation yield testing, the F3 lines were yield tested and a pedigree and bulk methods followed in F4 and F5. Each F5 line was bulked to provide seed for a yield test in F6. In the Single Seed Descent (SSD) procedure, a single seed was taken from each F2 plant to produce the F3 generation. The procedure was repeated for the F4 and F5. The F6 SSD lines and the F6 yield testing lines were compared in yield tests. The results showed that differences in yielding ability of F3 lines persisted over generations indicating that selection was effective. This was confirmed by the high significant correlations between F3 yields and those of later generations which ranged from r=0.51* to 0.85**. The grain yields of lines derived by the single seed descent procedure were as good as those derived from early generation yield testing. Significant linear correlation between visual rating of F3 and F6 yields with actual yields revealed that it is possible to identify promising lines of cowpea visually.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1573-5036
    Keywords: Calcareous soil ; Critical limit ; Rice Zinc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The DTPA-extractable Zn in 23 calcareous soils ranged from 0.34 to 3.42 ppm and the total Zn in rice leaves of control pots ranged from 15 to 50 ppm. The soil available Zn was negatively correlated with pH (r=−0.41*) and positively correlated with organic carbon (r=0.71**)_and rice tissue Zn concentration (r=0.98**). The Bray's per cent yield ranged from 29.12 to 126.36 and was positively correlated with available Zn (r=0.93**) and plant tissue Zn (r=0.91**). The critical Zn concentration in soil and plant below which plant response to Zn application to the soil may be expected, was 0.78 and 19 ppm respectively. In all the soils testing below 0.78 ppm Zn plants responded to Zn application and the per cent mean response at 5 and 10 ppm added Zn levels was 101.21 and 111.38 respectively. A negative response to applied Zn was recorded in soils of the high Zn group where the per cent mean response at 5 and 10 ppm added Zn was −14.90 and −33.78 respectively.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1573-5036
    Keywords: Organic manures ; Residual effects ; Rice ; Yield ; Zinc application ; ZnO suspension
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Application of zinc sulphate mixed with compost/poultry manure proved to be equivalent to the effect of dipping the seedling roots in 4% ZnO suspension with respect to rice yields but Zn-amended organic manures were superior to other treatments with regards to total Zn uptake. A marked residual effect of soil applied treatments was recorded on the succeeding maize crop. Application of poultry manure alone was about one and a half times more effective than compost alone in increasing the rice and maize grain yields. Poultry manure surpassed compost in increasing zinc uptake by the crops and at the same time it built up more available Zn in soil than compost for the following crop. The magnitude of yields and Zn uptake response were magnified when zinc sulphate was applied along with organic manures. Application of 25 kg zinc sulphate/ha alone had the same effect as 50 quintals poultry manure alone or 12.5 kg zinc sulphate applied with 50 quintals compost/ha with respect to crop yields. A significant positive correlation was, recorded in both the crops between Zn concentration in grain or straw and their respective yields.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1573-5036
    Keywords: Extractants for available Zn ; Hill and forest soils ; Rice ; Threshold value ; Zinc response
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The available Zn in 25 soils of Sub-Himalayan hill and forest region was determined by using some chemical extractants to evaluate its critical limit in soils and rice plant. The critical limit of soil available Zn using DTPA-CaCl2, DTPA-NH4HCO3, EDTA-NH4OAc and EDTA-(NH4)2CO3 was 0.76, 0.86, 0.85 and 1.18 ppm, respectively. The amount of Zn extracted by these extractants was positively and significantly correlated with per cent dry matter yield. In addition to per cent dry matter yield, the Zn extracted by DTPA-CaCl2, DTPA-NH4 HCO3 and EDTA-(NH4)2CO3 was also positively correlated with Zn concentration in 3rd leaf of rice, Zn concentration in rice shoots, Zn uptake by rice shoots and organic carbon content of the soil, and negatively correlated with soil pH.The 2N MgCl2 and 0.1N HCl extractants were found to be not suitable for these soils. Among the four promising extractants, EDTA-(NH4)2CO3 was most efficient as the value of critical limit determined by it expressed 82.4% predictability in the degree of accuracy against 36.8% with EDTA-NH4OAc. Hence EDTA-NH4OAc is the least efficient extractant for estimation of available Zn in such soils. The critical Zn concentration in 3rd leaf of rice was worked out to be 21.5 ppm below which economic responses to Zn application can be expected.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1573-5060
    Keywords: cowpea ; intercropping ; Nigeria ; yield stability ; Vigna unguiculata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Nine cowpea (Vigna unguiculata (L.) Walp.) breeding lines were grown in 13 experiments under sole crop and intercrop management, with and without insecticide application, in Nigeria. Cowpea was intercropped with cassava (Manihot esculenta Cranz), maize (Zea mays L.) and maize-cassava in the forest zone and with sorghum (Sorghum bicolor Moench.) and millet (Pennisetum glaucum (L.) R.Br.) in the savanna zone. Line by cropping system interactions were significant in 5 of 13 experiments and line by insecticide treatment interactions were significant in 2 of 13 experiments. Cowpea yield was severely depressed in intercropped plots and in plots to which no insecticide was applied. Among-environment variation in cowpea yield was greater when no insecticide was applied. Within each management treatment, the yield performance and stability of the cowpea lines was examined. Stability was assessed both by examining among-environment coefficients of variation and by regression analysis. Several of the breeding lines evaluated appeared promising under different levels of management and in a diversity of environments.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1573-5060
    Keywords: Striga gesnerioides ; Vigna unguiculata ; cowpea ; parasitic angiosperm ; breeding for resistance ; parasite variation ; races
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract An in vitro growth system was used to determine the virulence of two samples of Striga gesnerioides from Zakpota in southern Benin. Cowpea variety B301, previously considered resistant to all races of S. gesnerioides, was susceptible to both samples of the parasite. Two other cowpea varieties, 58–57 and IT81D-994, were totally resistant. Resistance in 58–57 was associated with a hypersensitive necrosis of infected roots, whilst IT81D-994 supported production of small S. gesnerioides tubercles with stems which failed to develop. Striga gesnerioides from southern Benin is the fourth race of the parasite to be identified, and the first with virulence on variety B301. The implications for breeding cowpeas with resistance to S. gesnerioides are discussed.
    Type of Medium: Electronic Resource
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