Authors:T. Vicheka, S. Yun, A.F. Lindain, M. Sopheareth, I.K. Chung, and K.M. Kim
This study was to determine the gene expression pattern and phenotypic change of Cheongcheong, Nagdong, TN1, and 8 different pedigrees of the CNDH population when WBPH infestation initiated at the reproductive stage of the crop. WBPH infested plants generally showed higher expression level of defense genes compared with the uninfected plants. LOX transcriptional levels in Nagdong and CNDH42-1 did not increase after WBPH feeding at all-time course. Chlorophyll content declined in infested plants compared to their controls, but still CNDH3, CNDH14-2, and CNDH65 were healthier. Heavy and extensive WBPH feeding affected rice yield and grain quality although the infestation started at the reproductive stage.
Authors:V. Damodaran, P. Subbian, and S. Marimuthu
A field experiment was conducted at Tamil Nadu Agricultural University from July 2001 to July 2002 to study the effect of different stubble management practices using biological inoculants on the growth and yield of rice in rice-based cropping systems. inoculation with Trichoderma viride during stubble incorporation followed by the application of 120 kg N ha-1 in 4 splits produced significantly taller plants, higher LAI and dry matter, a larger number of productive tillers, longer panicles with more filled grains and higher grain yield. However, it was on par with the stubble management practice involving Trichoderma viride followed by the application of 90 kg N ha-1 in 4 splits.
Brown planthopper (BPH) is one of the destructive insect pests causing significant yield losses in rice. BPH causes direct damage to the rice plants by sucking the sap from phloem, causing hopper burn and transmitting viral diseases like grassy and ragged stunt viruses. Several resistant donors have been identified from time to time, but the new biotypes of the pest arise to defeat the extended use of resistance genes in a single variety. This necessitates the regular identification of new resistant donors along with their nature of inheritance and gene action controlling the resistance. Knowing the inheritance pattern, gene action and number of genes controlling a trait helps the plant breeders to plan the effective breeding approaches for crop improvement. The present investigation was hence carried out to know the inheritance pattern, gene action and number of genes controlling BPH resistance in newly identified sources. The results indicated that the BPH resistance in PHS 29 genotype is under the control of single recessive gene. Whereas, it is controlled by two recessive genes in MRST 3 genotype. This reveals that relatively higher population size will be required to recover desirable segregants in the segregating populations involving MRST 3 genotype as one of the parents as compared to that involving PHS 29 genotype as parent. Since, the resistance in both the cases being recessive in nature, the trait will hence show significant additive effect, indicating that pure line development will be desirable for improvement of such a trait.
Crawford, R. D. (1964): The relationship between sowing date, latitude, yield and duration for rice ( OryzasativaL.). Tropical Agriculture Trinidad , 41 , 214-224.
The relationship between sowing date, latitude, yield and
Authors:F. Zhang, J. Li, X.L. Wang, W. Mao, H. Zhang, J. Guo, and J.W. Li
An allometric analysis of biomass and N mass allocation of rice (Oryza sativa L.) seedlings under non-shaded (100% of full sunlight) and shaded (30% of full sunlight) treatments were conducted. The allometric slopes and the intercepts were estimated using standardized major axis regression. Results indicated that biomass was preferentially allocated to stems during plant ontogeny, and leaves and roots were isometric when rice seedlings were not shaded. Under shade, however, more biomass was allocated to leaves and stems. N mass allocation was also altered by shading in that more N mass was allocated to the aerial shoots, and plants accumulated less N mass when shaded. Our study revealed that both biomass and N mass were in accordance with the optimal partitioning theory.
Authors:S. Rizvi, R. Sharma, T. Srinivas, A. Manan, A. Osmanzai, S. Siddiqui, K. Wadan, N. Hakimi, and A. Rahmani
The introduction of new crop varieties is important to improve farm productivity and increase food security in developing countries. This study was conducted to determine the performance of improved varieties of wheat (Triticum aestivum L.), rice (Oryza sativa L.), mungbean [(Vigna radiata (L.) Wilczek] and potato (Solanum tuberosum L.) in comparison to local varieties through farmers’ participatory evaluation. The study was conducted during three years (2006 to 2008) with 948 farmers’ participatory field trials across 18 districts in three Eastern provinces (Nangarhar, Laghman and Kunar) of Afghanistan. One or more improved varieties of wheat, rice, mungbean and potato were compared to the most popular local variety. Data were recorded on the grain yield of wheat, rice and mungbean, and the tuber yield of potato. On average, the improved varieties outyielded local varieties by 69, 57, 70 and 65% for wheat, rice, mungbean, and potato, respectively. Economic analysis in terms of net benefit demonstrated that the adoption of improved varieties resulted in additional incomes of US$ 1840, 1299, 574 and 790 ha-1 for wheat, rice, mungbean and potato, respectively. These findings underline the importance of on-farm farmers’ participatory technology evaluation in developing countries to disseminate new crop varieties to improve farm productivity.
Authors:Animesh Sarkar, Tofazzal Islam, Gokul Biswas, Shohidul Alam, Mikail Hossain, and Nur Talukder
The objectives of the research were to isolate phosphate solubilizing bacteria (PSB) from the rhizoplane of rice (Oryza sativa L.) cv. BRRIdhan 29 cultivated in acidic soils of Tangail in Bangladesh and evaluate their performances in phosphate solubilization in both in vitro and in vivo conditions. A total of 10 bacterial strains were isolated and purified by repeated streak culture on nutrient agar medium. Upon screening, five isolates (OS01, OS03, OS07, OS08 and OS10) showed varying levels of phosphate solubilizing activity in agar plate and broth assays. Among them, the strain OS07 (B1) and two previously isolated PSB strains B2 and B3 were selected for evaluation for their performances in rice alone or in combination of TSP (triple super phosphate: P1) and rock phosphate (P2). Plant height and the number of tillers per plant were significantly increased by all PSB isolates when used in combination with TSP but PSB alone did not influence much on plant height and the number of tillers except B1. The levels of mineral nutrients content in rice plant tissues were generally increased by the application of the PSB in combination with TSP, while the performances of B1 isolate was superior in all aspects to B2 and B3 isolates.
In Hungary rice (
L.) is cultivated under flooded conditions. Direct seeding into the soil is applied usually. The optimal sowing date is a key factor necessary to the success of this annual crop because of the relatively short growing season. The main objective of this research was to: (1) analyse duration of period from sowing to emergence at different temperature values, (2) determine base temperature of this phenophase and (3) establish a thermal time model for rice emergence. To do this, growth chamber experiments with 5 Hungarian cultivars were conducted to determine the time to median emergence (E
) at constant temperature of 14 to 34 °C in 2 °C steps. The sowing depth was 2 cm, and moisture was not a limiting factor. It was found that the critical thermal zone, which is of highest practical importance, is between 14 and 16 °C. At these values the E
is 23.9 and 13.4 days, respectively, showing a border between unfavourable and acceptable conditions. In the temperature interval between 26 and 34 °C the time needed for emergence was only 3.3 to 4.4 days. Variety differences were also detected. Base temperature was found between 9.8 and 10.9 °C. The thermal time requirements of 4 cultivars varied between 69 and 73 °C day. Data of field experiment with 9 sowing dates and a pot experiment with 3 sowings confirmed that our thermal time model can successfully simulate the emergence of rice.