Introgression of Gene for Non-Pollen Type Thermo-Sensitive Genic Male Sterility to Thai Rice Cultivars

For the two-line hybrid rice system, pol en sterility is regulated by recessive gene that responds to temperature. The recessive gene controlling thermo-sensitive genetic male sterility （TGMS） is expressed when the plants are grown in conditions with higher or lower critical temperatures. To transfer tgms gene（s） control ing TGMS to Thai rice cultivars by backcross breeding method, a male sterile line was used as a donor parent while Thai rice cultivars ChaiNat 1, PathumThani 1, and SuphanBuri 1 were used as recurrent parents. The BC2F2 lines were developed from backcrossing and selfing. Moreover, the simple sequence repeat （SSR） markers were developed for identifying tgms gene and the linked marker was used for assisting selection in backcrossing. The identification lines were confirmed by pol en observation. The results showed the success of introgression of the tgms gene into Thai rice cultivars. These lines will be tested for combining ability and used as female parent in hybrid rice production in Thailand.     

Phosphorus fractionation and adsorption characteristics in drinking water reservoir inlet river sediments under human disturbance

Journal of Soils and Sediments - Sediment phosphorus fractionation, adsorption kinetics, and adsorption isotherm characteristics were studied in two rivers, Muyang River and Lengshui River in...     

Long-Term Fertilizer Use Altered Soil Microbial Community Structure but Not α-Diversity in Subtropical Southwestern China

Eurasian Soil Science - Despite the general consensus that fertilizer is the most important driver of the evolution of soil microbial communities, the specific effects of long-term fertilizer use...     

3株烟草内生细菌促进作物生长作用的研究

通过漂浮育苗试验以及大田试验,研究了烟草内生细菌YN201408、YN201442和YN201448的促生长作用。结果表明:3个菌株的菌悬液均可促进烟草、番茄、白菜、玉米和油菜的生长,其中YN201448对烟草和番茄的促生长效果最好,YN201408促进白菜生长的作用较大,而YN201442对玉米和油菜的促生长作用最好。     

Salt Stress Effects on Germination,Plant Growth and Accumulation of Metabolites in Five Leguminous Plants

The investigation was conducted to determine physiological criteria of early selection for salt tolerant leguminous plants. Plants were subjected to 5 levels of salt stress at the roots （0, 50, 100,150 and 200 mM NaCI）. Results showed that sodium chloride had an underrating effect on growth of stems and seed germination of the species studied. The germination rates of seeds of Glycine max and Phaseolus vulgaris （sensitive glyeophytes） were affected from 3 g/L of NaCl, with critical thresholds at 9 and 12 g/L respectively. In contrast, critical thresholds with Mucunapoggei （facultative halophyte）, Vigna unguiculata （moderately tolerant glycophyte） and P. adenanthus （natural halophyte） was found to be above 21 g/L. The reduction of stems growth rate were not significant in P. adenanthus whereas in M. poggei and V. unguiculata this inhibition was observed just when nutritive solutions were enriched with 200 mM. The lipid contents were reduced in all the species under salt stress, whereas proteins and proline contents in the leaves were substantially increased in tolerant species （M. poggei, P. adenanthus and V. unguiculata）. In contrast, proteins and leaf proline contents were negatively affected by salt concentration to G. max and P. vulgaris. Seed germination, proteins and proline could be used as physiological criteria of early selection for salt tolerant leguminous plants.     

Identification and characterization of virulence-related effectors in the cucumber anthracnose fungus Colletotrichum orbiculare

The anthracnose fungus Colletotrichum orbiculare invades hosts and establishes biotrophy, later switching to necrotrophy, together with the secretion of an arsenal of effectors. In this review, we describe current progress in the study of pathogen effectors. We identified three virulence-related effectors in C. orbiculare, and revealed part of the strategy for effector-mediated infection, including suppression of immunity triggered by particular effectors. The virulence-related effectors accumulate in a unique interfacial region between C. orbiculare and cucumbers around the neck of primary biotrophic invasive hyphae. We found that the secretion of effectors toward the interface involves exocytosis and SEC22-dependent ER-Golgi traffic.     

Application of the Cropping System Model (CSM)‐CROPGRO‐Soybean for Determining Optimum Management Strategies for Soybean in Tropical Environments

The determination of optimum crop management practices for increasing soybean production can provide valuable information for strategic planning in the tropics. However, this process is time consuming and expensive. The use of a dynamic crop simulation model can be an alternative option to help estimate yield levels under various growing conditions. The objectives of this study were to evaluate the performance of the Cropping System Model (CSM)‐CROPGRO‐Soybean and to determine optimum management practices for soybean for growing conditions in the Phu Pha Man district, Thailand. Data from two soybean experiments that were conducted in 1991 at Chiang Mai University and in 2003 at Khon Kaen University were used to determine the cultivar coefficients for the cultivars CM 60 and SJ 5. The CSM‐CROPGRO‐Soybean model was evaluated with data from two experiments that were conducted at Chiang Mai University. The observed data sets from farmers’ fields located in the Phu Pha Man district were also used for model evaluation. Simulations for different management scenarios were conducted with soil property information for seven different soil series and historical weather data for the period 1972–2003 to predict the optimum crop management practices for soybean production in the Phu Pha Man district. The results of this study indicated that the cultivar coefficients of the two soybean cultivars resulted in simulated growth and development parameters that were in good agreement with almost all observed parameters. Model evaluation showed a good agreement between simulated and observed data for phenology and growth of soybean, and demonstrated the potential of the CSM‐CROPGRO‐Soybean model to simulate growth and yield for local environments, including farmers’ fields, in Thailand. The CSM‐CROPGRO‐Soybean simulations indicated that the optimum planting dates from June 15 to July 15 produced maximum soybean yield in a rainfed environment. However, the planting date December 15 produced the highest yield under quality irrigation. Soybean yield was slightly improved by applying nitrogen at a rate of 30 kg N ha^?1 at planting. Soybean yield also improved when the plant density was increased from 20 to 40 plants m^?2. The results from this study suggest that the CSM‐CROPGRO‐Soybean model can be a valuable tool in assisting with determining optimum management practices for soybean cropping systems in the Phu Pha Man district and might be applicable to other agricultural production areas in Thailand and southeast Asia.     

Effects of bioenergy crop cultivation on earthworm communities—A comparative study of perennial (Miscanthus) and annual crops with consideration of graded land-use intensity

Energy crops are of growing importance in agriculture worldwide. This field study aimed to investigate earthworm communities of different intensively cultivated soils during a 2-year period, with special emphasis on annual and perennial energy crops like rapeseed, maize, and Miscanthus. These were compared with cereals, grassland, and fallow sites. Distribution patterns of earthworm abundance, species, and ecological categories were analysed by constrained ordination procedures (redundancy analysis; CANOCO) using a set of environmental variables as predictors, such as CN value of harvest residues, SOC and N_t content, soil pH, soil texture, and land-use intensity. The latter was determined by principal component analysis using average soil coverage and intensity of tillage, weed control, and fertilisation as input variables. It was clearly found that land-use intensity was the dominant regressor for earthworm abundance and total number of species. The diversity of earthworm communities was especially enhanced and showed a more balanced species composition in extensively managed soils under grassland, fallow, and Miscanthus. For the total number of species, Miscanthus (5.1 ± 0.9) took a medium position and neither differed significantly from intensively managed rapeseed (4.0 ± 0.9), cereals (3.7 ± 1.1), and maize sites (3.0 ± 1.4), nor from grassland (6.8 ± 1.5) and fallow (6.4 ± 1.0) sites. Total earthworm abundance ranged between 355 (±132) and 62 (±49) individuals m⁻² in fallow and maize sites, respectively.Interestingly, Miscanthus had quite positive effects on earthworm communities although the CN value of harvest residues was very high. It is recommended that Miscanthus may facilitate a diverse earthworm community even in intensive agricultural landscapes.     

Response of pea (Pisum sativum L.) to mepiquat chloride under varying application doses and stages

Grown as a monoculture, peas (Pisum sativum L.) exhibit severe lodging after flowering and lodging causes yield reductions considerable. This study was conducted to investigate the effects of dose (untreated, 25, 50, 75 and 100 g a.i. ha^?1) and stage (late vegetative, early blooming and early pod filling) of mepiquat chloride (MC) application on the growth, lodging control, seed yield and yield parameters of pea (Pisum sativum L.) under field conditions in Erzurum, Turkey in 2002 and 2003. Application doses of 25, 50, 75 and 100 g a.i. ha^?1 significantly reduced stem height by 5.3 %, 7.2 %, 7.5 % and 6.4 % and increased stem width by 7.5 %, 12.7 %, 12.3 % and 15.7 % respectively, when compared with the untreated control, and thereby reduced the tendency of the crop to lodging. Increases of the seed yield under different application doses of MC ranged between 13.7 % and 20.1 % over the untreated control. However, in all parameters investigated, except for stem width, higher application doses of MC gave no clear advantages compared with the application dose of 25 g a.i. ha^?1. Seed yield was also significantly influenced by application stage of MC and application at early blooming stage of crop, MC significantly increased seed yield by 11.4 % and 10.2 % when compared with the late vegetative and the early pod filling stages respectively. Furthermore, the interaction of application dose and stage was significant, and spraying of pea plants with 25 g a.i. ha^?1 MC at early blooming stage has the most beneficial effects on the characters evaluated.