摘要:

AbstractThe influence of different weed types (grass, broadleaved and sedge species) on growth and yield parameters of mungbean (Vigna radiataL. Wilczek) was evaluated under field conditions. The presence of all types of weeks had the most significant effect on growth and yields of mungbean. Broadleaved species alone had a greater adverse effect than grasses, and the influence of sedges was the lowest. The adverse effect of weeds was most prominent on vegetative growth. The influence on yield components reduced with time. However, the adverse impact of weeds on yields was similar to that on vegetative growth. A significant correlation between weed biomass and yield loss was observed. The study indicated the critical competitive period to be in the vegetative phase. Some possible implications for selective weeding are presented.

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01123.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractTwo lentil cultivars, UJ1 and ILL, have been introduced into the farming system of the Middle East. The influence of P on their potential to fix N2under drought conditions is lacking. A factorial field experiment was carried out at Taibeh (500 mm yr−1) and Muru (300 mm yr−1), where three rates of P, two lentil cultivars and barley were included. Phosphorus was the main plot, while lentil and barley were grown randomly in the subplots. A typical experiment treated with unlabeled 100 kg N ha−1with similar P rates was conducted at the Taibeh site. Both cultivars on each site did not differ significantly at different levels of P regarding the biological yield. At each P level, both cultivars derived similar nitrogen percentages from atmosphere (per cent Ndfa), except at Taibeh with the intermediate rate of P, where ILL derived (66.1 %) compared to UJ1 (40.3 %). At Taibeh, the average percentages of N in the grain and straw were 4.17 % and 1.14%, respectively, and were significantly higher than at the Muru site (3.38 %, 1.29 %). The relatively drought‐like conditions at Muru reduced percentage Ndfa to ∼28 but this was increased by P addition. Nitrogen addition reduced partitioning of N (N index) from ∼0.70 % to ∼0.55 % and decreased P percentage in the grain from ∼0.40 % to ∼0.31 % and in straw from 0.11% to 0.07 % due to early maturation. In spite of the indigenousRhizobiumefficiency to fix N2, only 52.0 % and 42.3 % of the plant N was derived from the atmosphere at Taibeh and Muru, respectively, causing depletion of

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01124.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThe response to N fertilization of a short‐duration pigeonpea genotype, ICPL 87, was studied in the field to assess the scope for genetically improving symbiotic N2fixation by pigeonpea. The field study was undertaken during 1985, 1986 and 1987 growing seasons on Vertisol and Alfisol at ICRISAT Center (peninsular India), Inceptisol at Gwalior (central India) and Entisol at Hisar (northern India) in as non‐limiting environmental conditions as possible. Nitrogen fertilizer was applied to the soil at various growth stages to determine when N becomes most limiting. There was a significant response in grain yield to fertilizer N applied at flowering in Vertisol but not in Alfisol, Inceptisol or Entisol. This suggests that biological N2fixation by short‐duration pigeonpea was not adequate to meet N requirements of the crop grown in Vertisol but that it was probably adequate in the other three soil types. These results are discussed in relation to the nodulation and acetylene reductase activity of pigeonpea and also N mineralization potential of different soils. It can be concluded that there is a need for genetic improvement of N2fixing ability of short‐duration pigeonpea grown on heavy textured soils such as Ve

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01125.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractEight sweet potato cultivars (Ipomoea batatasLam.) were grown under four different light regimes (0, 26, 42 and 60 % light reduction (LR)) at two experimental sites of the International Potato Center (CIP) in Peru during the 1990 and 1991 growing season. Increasing shade diminished the tuber yield of five cultivars, two showed a tolerance for slight (26 % LR) and moderate (42 % LR) shade and one had the same yield in full sunshine and slight shade. Shade mainly reduced the sink‐size (tubers m−2) of sweet potato and to a lesser extent the sink‐strength. The growth of the plant top was hardly affected by shade; slight shade even favoured shoot development of some cultivars. The plant top was the stronger sink under shade conditions and tuber yield was not only reduced by lesser assimilate production as a whole but also by an altered assimilate partiti

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01126.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThe effect of planting date on the growth and yield of irrigated sunflower was investigated in 1992 and 1993. Two sunflower hybrids, Islero and Upsol‐veraflor, were sown at three different dates (3 October, 4 November, 2 December 1992 and 5 October, 6 November, 4 December 1993) in Sultan Qaboos University Agricultural Experiment Station on the Batinah Coast of Oman in a desert climate. Sunflower planted in December emerged later, flowered later and matured later than that planted in October or November. Severity of stalk lodging was closely related to the extent of stem weevil infestation, which was more serious in the early planted sunflower. Sclerotina head rot was also most severe in the October plantings and least severe in the December plantings. Head diameter, number of seeds per head and percentage of large seeds increased with delay in planting date. Seed yield and oil yield were highest in the December planted sunflower but oil concentration was not affected by the planting date. Based on these results, a December planting date was recommended for the Batinah Coast of Oman and other areas with similar climatic condition

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01127.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractCardamom is a popular and important tropical spice, traditionally propagated by rhizomes, although seeds which are considered recalcitrant are being increasingly used in planting programmes. Thus a study evaluated the effects of pod maturity on pod, seed and germination characteristics of three popular varieties, along with the influence of drying on seed germinability.Green and yellow mature pods and seeds of all varieties had a high moisture content. The variety Mysore, which is considered high yielding, had larger pods with a greater number of heavy seeds. Although the pods of Vazukka were heavier than the Malabar variety due to greater seed weights, seed numbers were similar in both varieties. Seed moisture contents declined with increasing pod maturity, while seed weights and germinability increased.The germinability of Mysore seeds were greater, while that of the other varieties were lower. The larger seeds of all varieties germinated 15–20 days earlier, giving rise to a greater percentage (20–25 %) of seedlings. Desiccation at 20 °C maintained germinability for a longer period (5–9 days) in all varieties, than when dried at 30 °C. The seeds of the variety Mysore was more tolerant to desiccation than other varieties. The study illustrated the importance of selecting large seeds from yellow mature pods of cardamom for propagation and the value of establishment immediately after harvest to obtain a greater number of se

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01128.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractChickpea (Cicer arietinumL.) is normally grown as a spring‐sown rainfed crop in the Mediterranean region in areas receiving more than 400 mm of rainfall annually. Because of large fluctuations in the total amount and distribution of the rainfall, the crop occasionally suffers from extreme terminal drought. Breeders face a dilemma in selecting materials for both normal moisture regimes and drought conditions because it is often difficult to conduct two parallel breeding programmes. This study examines the transferability of the selection indices (developed as a multiple regression of yield on most influential traits) from one environment to another with the objective of selecting an appropriate environment for the development of cultivars adapted to both environments. Experiments were conducted for 3 years (1989‐1991) during the spring at two locations with normal moisture regime (hereafter referred to as drought‐free) in Syria and Lebanon and one drought‐prone location in Syria. Each year, 192‐240 newly bred lines were evaluated in replicated trials for seed yield, days to flowering and maturity, plant height and 100‐seed weight. Correlation analyses showed that increased seed size, early maturity and reduced plant height at the drought‐prone location and early maturity at the drought‐free location were of prime importance in increasing seed yield. Regression equations developed to predict seed yield showed that days to flower and maturity accounted from 67‐80 % variation in seed yield at the dry location, whereas at the drought‐free locations the contribution of days to maturity was smaller except in 1991 in Lebanon. The percent success in the transferability of the selection indices from the drought‐free environments to the drought‐prone environment was higher than that from the drought‐prone environment to the drought‐free environment. These results indicate that chickpea breeding material developed under drought‐free environments could be useful under drought‐prone conditions. Early‐maturing lines selected under normal environments would also pe

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01129.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Books Reviewed in this Article:Bajaj, Y. P. S. (ed.) Biotechnology in Agriculture and Forestry. Vol. 27. Somatic Hybridisation in Crop Improvement I.Leigh, R. A. and A. E. Johnston (eds.): Long‐term Experiments in Agriculture and Ecological Sciences.Diercks, R. und R. Heitefuß (Hrsg.), Integrierter Landbau.Klimek, S., Stand der Triticale‐Forschung in Polen (Winter‐ und Sommertriticale). Heraus‐gegeben von M. Zoschke. Osteuropastudien der Hochschulen des Landes Hessen. Reihe I: Gießener Abhandlungen zur Agra‐ und Wirtschaftsforschung des europäischen Ostens.Allen, P. (ed.), Food for the Future. Conditions and Contradictions of Sustainability.Virmani, S. S.: Heterosis and Hybrid Rice Breeding. Monographs on Theoretical and Applied

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01130.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY