New varieties overcame the"cancer of rice

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Quality of principal released rice varieties in China

Most of the cultivated rices in China are nonwaxy japonica and indica varieties. According to the the survey of the rice quality on 262 principal released varieties (every variety has been popularized over 6,600 ha) by CNRRI, the average of brown rice recovery is 80% (70—82%) and the head rice recovery is 54% (40—67%)in indica varieties. Most indica varieties have medium long and bold grains with low translucency and high rate of chalky grain and chalkiness. In addition, they possess high amylose content, low to medium gelatinization temperature and medium gel consistency with average 9.8% protein content (6.8% to 13.8%). Only a few indica varieties have extra long or slender grains, high translucency, medium or low amylose content, and soft or hard gel consistency. None of them have high     

Exploitation of genetic variation caused by space treatment in rice

Seeds of early indica rice varieties 6188, D6049, of late indiea rice varieties Minghui 63, Xiangge, Waiqi, 70321, and late japonica rice variety Beik 15 were carried by the retrieved satellite "921006" in order to investigate the comprehensive effects of the space factors. Treated seeds and untreated seeds (CK) were grown in the field. The results showed that although compared with the CK (which was very uniform) small differences on population uniformity, plant height, growth duration and seed setting rate were observed, no segregation was found in SP_1. Strong segregation occurred in SP_2 and SP_3 generations. Significant difference on the grain yield of Single plant was observed between SP_2 and CK, while the yield between     

Effects of rice or wheat residue retention on the quality of milled japonica rice in a rice–wheat rotation system in China

In rice–wheat rotation systems, crop straw is usually retained in the field at land preparation in every, or every other, season. We conducted a 3-year-6-season experiment in the middle–lower Yangtze River Valley to compare the grain qualities of rice under straw retained after single or double seasons per year. Four treatments were designed as: both wheat and rice straw retained(WR), only rice straw retained(R), only wheat straw retained(W), and no straw retained(CK). The varieties were Yangmai 16 wheat and Wuyunjing 23 japonica rice. The results showed contrasting effects of W and R on rice quality. Amylopectin content, peak viscosity, cool viscosity, and breakdown viscosity of rice grain were significantly increased in W compared to the CK, whereas gelatinization temperature,setback viscosity, and protein content significantly decreased. In addition, the effect of WR on rice grain quality was similar to that of W, although soil fertility was enhanced in WR due to straw being retained in two cycles. The differences in protein and starch contents among the treatments might result from soil nitrogen supply. These results indicate that wheat straw retained in the field is more important for high rice quality than rice straw return, and straw from both seasons is recommended for positive effects on soil fertility.     

Genetic diversity and population structure of rice blast fungus in China

Rice blast resistance has been unreliable insome cases with the field breakdown of previ-ous resistant cultivars occurring within a fewyears.To eventually develop better breedingstrategies,we combine MGR—DNA finger-printing and pathotyping to determine the pop-ulation structure of the pathogen and the rela-tionship between the structure and virulencediversity of the pathogen in China.The MGR—DNA fingerprints of 40 isolates collectedfrom 108 different sites among 12 provinces(municipality)during 1980—1994 have beenstudied with a dispersed repeated sequenceprobe MGR586/EcoR 1 digest combination.The fingerprint data document a generalizedgenetic organization.Forty—five pathotypesof P.ricsea could be distinguished into 54 sepa-rate lineages based on MGR—DNA fingerprint     

Tolerance evaluation of rice varieties to the brown plan-thopper,Nilaparvata lugens feeding

The brown planthopper, Nilaparvata lugens (Stal) (BPH) is one of the most important insect pests of rice in China and other east-southern Asian countries. Utilization of rice resistance varieties is one of the most e-conomic and effective ways for controlling N. lugens . The resistance of rice varieties declined due to the change of BPH biotype. The current resistance screening methods based on biotic reaction also may eliminate numerous rice varieties with high-yielding and/ or good grain quality which were not resistant to BPH but had strong tolerance to BPH.     

Properties of the pigment in black rice

Pigment was extracted from pericarp of black rice variety Zixiangnuo. The effects of several factors, including pH, light, chemical reagents and foodstuff additives on the color, solubility and heat stability of the pigment were observed. The color of the pigment varied with different acid conditions. When the pH was below 3, a stronger absorption peak at 495nm was observed. If the pH was between 3 and 10, there was a platform in 400-495nm. No obvious absorption peak in visible light region was found when pH was above 10. As the pH increased, the color of the pigment changed, from deep red to light red until to yellowishbrown, e.g. pH 0-2, deep red; pH3-4, red pH5-6, quite red; pH9-10, faint red; pH11, faint brown yellow; pH12, light brown yellow; pH13, yellowish brown; pH14, deep yellowish brown. The change of color was reversible. The pigment was quite stable under nature light conditions. At pH 1, it was basically unchanged within 10 d under sunlight or within 60 d under indoor nature light. However,     

On-farm soil N supply and N nutrition in the rice–wheat system of Nepal and Bangladesh

On-farm research to evaluate the productivity and nitrogen (N) nutrition of a rice (Oryza sativa L.)–wheat (Triticum aestivum L.) cropping system was conducted with 21 farmers in the piedmont of Nepal and with 21 farmers in northwest Bangladesh. In Nepal, two levels of N-fertilizer (0–22–42 and 100–22–42 kg N–P–K ha⁻¹) and farmers’ nutrient management practices were tested in the rice season, and three levels of N (0–22–42, 70–22–42, and 100–22–42) and farmers’ practices were evaluated in the wheat season. The treatments in Bangladesh included a researchers managed minus-N plot (0–22–42) and the farmers’ practices. Rice and wheat yields were higher in all treatments than the 0–22–42 control plots, with the exception of rice with the farmers’ practices at one location in Bangladesh. The researchers’ treatment of 100–22–42 in Nepal resulted in larger yields of both rice and wheat than the farmers’ practices, indicating that farmers’ rates of N-fertilizer (mean 49 kg N ha⁻¹) were too low. Delaying wheat seeding reduced yields in the fertilized plots in both countries, especially as N-fertilizer dose increased. Soil N-supplying capacities (SNSC), measured as total N accumulation from the zero-N plots (0–22–42), and grain yields without N additions were greater for rice than for wheat in both Nepal and Bangladesh. Higher SNSC in rice was probably due to greater mineralization of soil organic N in the warm, moist conditions of the monsoon season than in the cooler, drier wheat season. However, SNSC was not correlated with total soil N, two soil N availability tests (hot KCl-extractable NH₄⁺ or 7-day anaerobic incubation), exchangeable NH₄⁺ or NO₃⁻. Wheat in Nepal had greater N-recovery efficiency, agronomic efficiency of N, and physiological efficiency of N than rice. Nitrogen internal-use efficiency of rice for all treatments in both countries was within published ranges of maximum sufficiency and maximum dilution. In wheat, the relationship between grain yield and N accumulation was linear indicating that mobilization of plant N to the grain was less affected by biotic and abiotic stresses than in rice.     

The location of 5’-nucleotidase in seedling cells in Yunnan rice varieties and the change of enzyme activity after chilling injury

The seedlings of three rice varieties(Damagu,Ligeng 2,and Xiuzinuo)were cultivated at 25     

Chromosome location of a gene for aroma in rice

Scented or aromatic rice (Oryza sativa L.) is highly valued in many areas of the world. The development of high yielding scented cultivars has been limited because of lacking information on the inheritance of scent such as linkage of genes for aroma with other genes. We report here our studies on the determination of the chromosomal location of an aroma gene. Twenty-nine marker stocks, including 14     

Fantastic yields in the system of rice intensification: fact or fallacy?

The combination of natural resources, genes, weather and management systems largely determines maximum crop yields. Recently, one of those elements was portrayed as the key to releasing hitherto unrecognized, but significant, untapped growth potential in rice. That element, the system of rice intensification (SRI), is an unconventional management system developed in Madagascar, where it was reported to increase rice yields to ‘fantastic’ levels. To investigate the general potency of the SRI, we conducted experiments in three locations in China comparing yields in conventional and SRI management systems. In addition, we used a theoretical model to predict maximum yields and compared those with reported yields for various locations, including China and Madagascar. Our results imply that the SRI has no inherent advantage over the conventional system and that the original reports of extraordinary high yields are likely to be the consequence of error.     

Analysis of genetic effects and heritabilities for amylose content of indica rice in different environments

An understanding of the genetic effects of em-bryo genes for rice quality traits is of impor-tance for rice quality improvement. Analysisof embryo, endosperm, cytoplasmic, and ma-ternal genetic effects and genotype×environ-     

Distribution of the Si-deficiency rice soil in Hubei Province

There are about 1 million ha of Si-deficiency paddy soils in Hubei Province. Practically, it is essential to study the Si nutrient status in those Si-deficiency rice soil and its regional distribution before the application of Si-fertilizer. According to the analysis of 50 rice soil samples which collected from 20 counties/cities in Hubei Province, the available Si content in rice soils derived from different parent materials varied greatly. The Si content from high to low was in sequence of limestone, redpurplish sandy shale with carbonate, alluvium and lacustrine deposits, quaternary period red clay, granitic gneiss, and sandy shale. In addition, the Si content in rice soil was remarkably related with its pH. It seems that the pH 6.5 might be a demarcation line that divided the supplying Si ability of rice soils into the low and high categories (Table 1). Integrating the results with a critical soil Si-deficiency as 100 mg/kg, the evaluation index of soil Si supplying capability of a rice soil     

Distribution of the Si-deficiency rice soil in Hubet Province

There are about 1 million ha of Si-deficiency paddy soils in Hubei Province, Practically, it is essential to study the Si nutrient status in those Si-deficiency rice soil and its regional distribution before the application of Si-fertilizer.     

Effect of intermittent irrigation following the system of rice intensification (SRI) on rice yield in a farmer’s paddy fields in Indonesia

System of rice intensification (SRI) has been disseminated in many countries because of its high yield, although the mechanism of yield increase has yet to be fully understood. The aims of this study were to clarify the actual water management of a skilled SRI farmer in irrigated paddy field of Indonesia and to examine the effect of intermittent water management on rice growth and yield. Yield and yield components were compared in the field experiments in the farmer’s fields under intermittent (SRI) or flooded (FL) irrigation for 4 years from 2013 to 2016. The daily mean water depth of SRI plots during 0–40 days after transplanting showed very shallow (ca. 2 cm) or little lower than soil surface and continued to be lower than soil surface during reproductive stage when panicles were formed. The yield of SRI significantly exceeded that of FL for 4 years by 13% (P?=?0.0004), so did the panicle numbers per area (P?=?0.036). The yield increase in SRI was associated with the increased number of panicles, which should have resulted from enhanced tiller development under shallow water level during the vegetative stage. The increased number of panicles was, however, counteracted by the reduced number of spikelets per panicle and resulted in nonsignificant increase in the spikelet density, defined as number of spikelets per unit area of crop. This dampening change in spikelet number per panicle could have been caused by limited supply of either nitrogen or carbohydrate during the panicle development stage under the intermittent water supply. A greater yield increase by SRI could be expected by improving nutrient or water management during the reproductive stage.     

Analysis of genetic effects and correlations for nutrient quality traits of indica rice in different environments

Understanding the variation for the expressionof genes in different environments is one of themajor goals in qualitative genetics. In this pa-per, the genetic models for quantitative traitsof endosperm in cereal crops were used to eval-uate the seed, cytoplasm and maternal geneticeffects as well as the genotype × environment(GE) interaction effects, and to predict thebreeding value of parents and genotypic corre-lation for nutrient quality traits of indica rice (Oryza sativa L.).     

Expression of a barley ABA-responsive protein gene in transgenic rice

A cDNA clone encoding an ABA-responsive protein HVA1, was isolated by differential screening from barley aleurone layers (Hong et al.), Expression of the HVA1 gene is shown to be developmentally regulated, organ specif ic, and ABA and stress-induced (Hong et al.). Transgenlc tobacco plants constitutively expressing HVA1 protein displayed a 4-day delay of leave wilting under drought conditions and a lower water content threshcdd (39% vs 47.6%) at the time point of first wilting. These data indicate that HVA1 protein may play a role in plant tolerance to drought