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Emily Rutto Cody Daft Jonathan Kelly Bee Khim Chim Jeremiah Mullock Guilherme Torres 《Journal of plant nutrition》2014,37(2):198-208
Uneven crop stands result in a reduction in corn yield production. This study was conducted to determine the effect of delayed emergence on corn yields and the effect of nitrogen (N) applications to compensate for yield reductions. The design used was a randomized complete block, with 4 sequences of delayed planting (0,4,7,and 10 days after planting) and 3 rates of nitrogen fertilizer (0, 40, 80 kg N ha?1). At maturity, individual plants were tagged in sets of three and hand harvested. Corn ears were shelled, and yield per plant calculated. Grain yield of the delayed plant compared to that of the neighbors was reduced by 27, 8, 20 and 12 kg ha?1day?1 for 2007 LCB1, 2007 LCB2, 2010 LCB1 and 2010 LCB2, respectively. Over locations and years, the mean grain yield decrease of the delayed plant versus neighboring plants for each day delay was 122 kg ha?1. 相似文献
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Nelly Wabete Liet Chim Dominique Pham Pierrette Lemaire Jean-Charles Massabuau 《Aquaculture (Amsterdam, Netherlands)》2006,260(1-4):181-193
The consequences of handling stress (fishing, transfer, eyestalk ablation) on shrimp broodstock are poorly documented. The weakness of farmed shrimp, Litopenaeus stylirostris, during winter is a major problem in New Caledonia, because of seasonal climate (tropical–sub-temperate). The transfer of broodstock in winter from earthen outdoor ponds to indoor maturation tanks in the hatchery (T = 20 °C, Salinity = 35‰, fed shrimp) usually leads, after 48 h, to high mortality (up to 70%). Eyestalk ablation to induce ovarian maturation in females leads to further mortality.
Starting from a background analysis of physiological disturbances (initial osmoregulatory imbalance) associated with handling stress (Wabete, N., Chim, L., Lemaire, P., Massabuau, J.-C., 2004. Caractérisation de problèmes de physiologie respiratoire et d'échanges ioniques associés à la manipulation chez la crevette pénéide Litopenaeus stylirostris à 20 °C. Styli 2003. Trente ans de crevetticulture en Nouvelle-Calédonie. Ed. Ifremer. Actes Colloq. 38, 75-84.), we developed a protocol using a soft technology, based on modifications of water salinity, temperature and feeding regime. The aim was to minimize problems of osmoregulatory imbalance and associated mortalities. The protocol we developed, called the LSD OT protocol (Low Salinity and Diet, Optimal Temperature), was first evaluated on sub-adult shrimp (20–25 g) and then applied to broodstock. Survival after transfer and following eyestalk ablation, as well as reproductive achievement (spawning rate, nauplii number) was considerably improved when shrimps were transferred under “physiological comfort” i.e. warmed isosmotic water (26 °C and 26‰) and unfed for 3 d. This new handling protocol, based on a better control of salinity, temperature and feeding conditions, has been transferred successfully to private hatcheries and already contributes to an increased profitability of New-Caledonian shrimp industry. 相似文献
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L Chim P Lemaire M Delaporte G Le Moullac R Galois & J L M Martin 《Aquaculture Research》2001,32(2):91-94
The prawn Penaeus stylirostris (Stimpson), when fed for 28 days with n‐3 highly unsaturated fatty acid (HUFA)‐enriched feed pellets, demonstrated an enhanced resistance to variations in environmental parameters (a decrease in temperature and salinity over a 4‐day period from 28 °C to 17 °C and from 35‰ to 10‰ respectively) and an improvement in their immune defence potential, i.e. increased agglutination titre of plasma and increased respiratory burst of haemocytes. 相似文献
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Hue Thi Nguyen Quang Hong Vu Tan Van Mai Thu Thi Nguyen Lam Duc Vu Tung Thanh Nguyen Long Viet Nguyen Hien Thu Thi Vu Hue Thi Nong Trung Nguyen Dinh Nakano Toshitsugu Liet Van Vu 《水稻科学》2018,25(1):52-56
Bacterial leaf blight of rice (BLB), caused by Xanthomonas oryzae pv. oryzae, is one of the most destructive diseases in Asian rice fields. A high-quality rice variety, LT2, was used as the recipient parent. IRBB21, which carries the Xa21 gene, was used as the donor parent. The resistance gene Xa21 was introduced into LT2 by marker-assisted backcrossing. Three Xoo races were used to inoculate the improved lines following the clipping method. Eleven BC3F3 lines carrying Xa21 were obtained based on molecular markers and agronomic performance. The 11 lines were then inoculated with the three Xoo races. All the 11 improved lines showed better resistance to BLB than the recipient parent LT2. Based on the level of resistance to BLB and their agronomic performance, five lines (BC3F3 5.1.5.1, BC3F3 5.1.5.12, BC3F3 8.5.6.44, BC3F3 9.5.4.1 and BC3F3 9.5.4.23) were selected as the most promising for commercial release. These improved lines could contribute to rice production in terms of food security. 相似文献
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Chimène Fanta Abib Mama Ntoupka Régis Peltier Jean-Michel Harmand Philippe Thaler 《Agroforestry Systems》2013,87(2):427-438
Gum arabic production from Acacia senegal is lower in sub-humid areas than arid areas. Water stress is thought to be the reason for higher yields in arid areas. The application of ethephon is thought to mimic the effect of water stress in other plants. The objective of this study was to determine if the application of ethephon would increase the gum yields of Acacia senegal under sub-humid conditions in Cameroon. Trees receiving 40 or 120 mg ethephon were compared to controls in field experiments at a semi-arid and a sub-humid location in Northern Cameroon, over two seasons. Two provenances from drier areas (Sudan) were compared to the local one. In the first season, gum yield of the local provenance treated with ethephon was increased by 400–600 % compared to the untreated trees. Gum yield at the semi-arid location was 77, 313 and 214 g/tree with 0, 40 and 120 mg ethephon/tree, respectively, while at the sub-humid location, it was 30, 186 and 114 g/tree with 0, 40 and 120 mg ethephon/tree. However, in the second season, the effect of ethephon was not significant in the semi-arid area, whereas it was evident in the sub-humid area (up to 478 g/tree). Moreover, ethephon did not affect gum yield of provenances from drier areas (Sudan). This showed that the water-stress hypothesis has to be refined. The development of ethephon-based tapping systems is promising, but requires further studies with a wider range of environmental conditions and A. senegal provenances. 相似文献
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Hulme M Mahony M Beck S Görg C Hansjürgens B Hauck J Nesshöver C Paulsch A Vandewalle M Wittmer H Böschen S Bridgewater P Diaw MC Fabre P Figueroa A Heong KL Korn H Leemans R Lövbrand E Hamid MN Monfreda C Pielke R Settele J Winter M Vadrot AB van den Hove S van der Sluijs JP 《Science (New York, N.Y.)》2011,333(6043):697-698
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Yesuf Assen Mohammed Jonathan Kelly Bee Khim Chim Emily Rutto Kevin Waldschmidt Jeremiah Mullock 《Journal of plant nutrition》2013,36(5):749-761
From 2002 to date, a long-term field experiment has been conducted at Lake Carl Blackwell, Oklahoma, with different rates and times of nitrogen (N) fertilizer application to determine their effect on grain yield, protein and N uptake of winter wheat. Trend analysis for N rates (0, 50, 100, 150 and 200 kg N ha?1) and orthogonal contrasts for different application times (pre-plant, top-dressed in February and March) were performed. With increasing fertilizer N, wheat grain yield and protein content increased from 2110 kg ha?1 to 6783 kg ha?1 and from 8.96 to 17.19%, respectively. For grain yield, protein, and N use efficiency, split applications of N fertilizer were much more efficient than applying all N pre-plant. Large differences in grain yields were noted for different years at the same N rate (range exceeded 5.0 Mg ha?1) and that illustrated the need for making within-year-specific N rate recommendations. 相似文献
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Our study showed that osmoregulatory capacity (OC) of shrimp from the same clutch displayed interindividual variability. When environmental salinity decreases, this variability increases. Thus, at isoosmotic point (sea‐water salinity ≈26), the coefficient of variation calculated for measured OC was 2.7%, whereas it was 8.2% for sea‐water salinity ≈1.5. In terms of haemolymph osmolality, the interindividual difference can reach up to 45.8% for the same water salinity level. The mean OC of individuals that have survived a series of salinity and temperature shocks is significantly greater than the mean value recorded within their original population. This increase in OC was maintained beyond the one or two moulting periods that these shrimp experienced during our experiment. 相似文献
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Vu Van Liet Nguyen Thi Thuy Linh Nguyen Thi Thuy Vu Thi Bich Hanh Pham Quang Tuan Nguyen Thi Phuong Thao 《广西农业科学》2011,(9):1029-1034
【目的】利用ISSR分子标记分析越南北部山区当地玉米种质材料的遗传多样性。【方法】采用ISSR技术和10个引物对从越南和老挝北部山区3个省收集的21份玉米种质材料即12份普通玉米和9份糯玉米的遗传多样性进行分析。【结果】在21份玉米种质材料中可以检测到108个ISSR片段,其多态性为100%。ISSR引物的多态性信息量值为0.10～0.39,每条引物平均为0.24;分辨力为14.29~0.48,平均每条为4.48。除ISSR-T1以外,所有ISSR引物在13份玉米材料中均产生特异性片段。根据聚类分析结果,使用70%的遗传相似性作为切割点,建立了玉米种质材料系统树,21份玉米种质材料被分为3大类。不同玉米材料的相似系数为0.52~0.90.【结论】ISSR标记可提供玉米种质遗传多样性信息,对越南玉米种质材料的收集、保护和育种具有重要作用。 相似文献