The genetic relationship between popping expansion volume and two yield components in popcorn using unconditional and conditional QTL analysis

Popping expansion volume (PEV) is the most important quality trait in popcorn, while its germplasm is inferior to normal dent/flint corn in yield. In this study, 259 F_2:3 families, developed from the cross between a dent corn inbred Dan232 and a popcorn inbred N04, were evaluated for their PEV, grain weight per plant (GWP) and 100-grain weight (100 GW) in two environments. The genetic relationship between PEV and GWP, and 100 GW on individual gene loci were evaluated using unconditional and conditional QTL mapping methods. In total, five, one and three unconditional QTL were identified for PEV, GWP, and 100 GW, respectively. The positive alleles of all QTL for PEV were from N04, while positive alleles of all QTL for GWP and 100 GW were from Dan232. In conditional mapping, one and two QTL failed to be detected, and all four additional QTL were detected. Nevertheless, three QTL were identified, which controlled PEV independently from GWP/100 GW. They seemed to be potential candidates in popcorn breeding to increase PEV without decreasing GWP/100 GW. The results suggested that for significantly correlated traits, the conditional QTL mapping method could be used to dissect the genetic interrelationship between traits at the level of individual QTL, as well as reveal additional QTL that were undetectable by unconditional mapping.     

The inheritance of chemical phenotype in <Emphasis Type="Italic">Cannabis sativa</Emphasis> L. (III): variation in cannabichromene proportion

The mechanism that controls the proportion of cannabichromene (CBC), a potential pharmaceutical, in the cannabinoid fraction of Cannabis sativa L. is explored. As with tetrahydrocannabinol (THC) and cannabidiol (CBD), CBC is an enzymatic conversion product of the precursor cannabigerol (CBG). CBC is reported to dominate the cannabinoid fraction of juveniles and to decline with maturation. This ontogeny was confirmed in inbred lines with different mature chemotypes. A consistent CBC presence was found in early leaves from a diverse clone collection, suggesting that CBC synthase is encoded by a fixed locus. Morphological variants possessing a ‘prolonged juvenile chemotype’ (PJC), a substantial proportion of CBC persisting up to maturity, are presented. PJC is associated with a reduced presence of floral bracts, bracteoles, and capitate-stalked trichomes. Genetic factors causing these features were independent of the allelic chemotype locus B that was previously postulated and regulates THC and CBD synthesis and CBG accumulation. In contrast to previously described Cannabis chemotypes, the cannabinoid composition of PJCs showed plasticity in that reduced light levels increased the CBC proportion. The ability of PJC plants to enable the production of pharmaceutical raw material with high CBC purity is demonstrated.     

The Optimization for Crop Planning and Some Advances for Water-Saving Crop Planning in the Semiarid Loess Plateau of China

The establishment of water-saving crop planning is an inevitable choice of the water-saving agriculture for the water-deficiency region in the arid and semiarid Loess Plateau of China and the world. The water-saving crop planning refers to the planting structure that centres the adjustment of the crop's adaptation to water, the optimization of temporal and spatial layout for crops, the local natural resources, marketing resources, human resources and financial input to enable region or basin with limited water resources to achieve the maximum economic, social and ecological benefits of planting industry under certain technology and economy. After the analysis on the research progress of optimization theory, optimization goals, optimization methods of water-saving cultivation structure and macro-control measures, it is pointed out that the main deficiencies of the current research of water-saving cultivation pattern optimization are lacking of a strong theoretical basis, and the immaturity of optimization technologies. The future crucial research direction will focus on five aspects such as the special optimization theory system, the division methods by studying the watershed unit and using 3S technology, optimization model based on multi-objective evolutionary algorithm, evaluation of rationality and macro-control measures on the basis of the public participation.     

Starch Content and Granule Size Distribution in Grains of Wheat in Relation to Post-Anthesis Water Deficits

Post-anthesis soil moisture condition is closely associated with grain yield and quality in wheat ( Triticum aestivum L.). To investigate the effect of post-anthesis water deficit (WD) on starch content and granule size distribution, pot-experiments were conducted in 2006–2007 and 2007–2008 growing seasons, using five wheat cultivars with different amylose content. The result showed that the grain starch granules had a bimodal curve in the volume and surface area distribution, and a unimodal curve was found in number distribution. Post-anthesis WD reduced the B-granules (<10 μm in diameter) volume % and surface area % in Nuomai50206 and Gaocheng8901, increased the proportion in Weimai10, whereas the effect on those in Jinan17 and Shannong15 was not significant. Post-anthesis WD decreased the number % of <2 μm starch granules, significantly in all cultivars. The amylose content was negatively correlated with the volume of <10 μm and positively correlated to >15 μm starch granules, respectively, suggesting that small starch granules (<10 μm) are low in amylose content, whereas, big starch granules (>15 μm) are high. The results indicate that the grain starch granule size distributions of Jinan17 and Shannong15 with high amylose content were less affected by WD, than those of Nuomai50206 and Gaocheng8901 with low amylose content.     

A QTL controlling low temperature induced spikelet sterility at booting stage in rice

Low temperature is a major abiotic stress for rice cultivation, causing serious yield loss in many countries. To identify QTL controlling low temperature induced spikelet sterility in rice, the progeny of F2, BC1F1 and BC2F1 populations derived from a Reiziq × Lijiangheigu cross were exposed to 21/15°C for 15 days at the booting stage, and spikelet sterility was assessed. For genotyping, 92 polymorphic markers from 373 SSR and 325 STS primer pairs were used. A major QTL was initially indentified on the short arm of chromosome 10 by selective genotyping using highly tolerant and susceptible progeny from F2 and BC1F1 populations. The QTL (qLTSPKST10.1) was validated and mapped by genotyping the entire F2 (282 progeny) and BC1F1 (84 progeny) populations. The results from the F2 population showed that qLTSPKST10.1 could explain 20.5% of the variation in spikelet sterility caused by low temperature treatment with additive (a = 14.4) and dominant effect (d = −7.5). From the analysis of 98 selected BC2F1 progeny, the QTL located in the 3.5 cM interval between S10010.9 and S10014.4 was further confirmed. Based on the studies of 3 generations in 2 years, it was clear that the QTL on chromosome 10 is a major determinant of the control of low temperature induced spikelet sterility at booting stage.     

大豆品种的再生性能及对EHA 101农杆菌的敏感性

大豆转化可利用农杆菌和子叶节转化系统,bar基因作为选择标记,草丁膦作为选择试剂.用5-6 d发芽的种子的子叶节作外植体,在子叶节处划5-6下,用含pPTN 140的农杆菌EHA 101感染后,共培养3 d,用含抗生素的洗液洗去外植体上的农杆菌,将外植体放入5 mg/L草丁膦的长芽培养基,两周后统计不同大豆品种的再生率,4周后做GUS染色对含pPTN1     

Intensification of New Zealand beef farming systems

This study used whole-farm management, nutrient budgeting/greenhouse gas (GHG) emissions and feed formulation computer tools to determine the production, environmental and financial implications of intensifying the beef production of typical New Zealand (NZ) sheep and beef farming systems. Two methods of intensification, feeding maize silage (MS) or applying nitrogen (N) fertiliser, were implemented on two farm types differing in the proportions of cultivatable land to hill land (25% vs. 75% hill). In addition, the consequences of intensification by incorporating a beef feedlot (FL) into each of the farm types were also examined.Feeding MS or applying N fertiliser substantially increased the amount of beef produced per ha. Intensifying production was also associated with increased total N leaching and GHG emissions although there were differences between the methods of intensification. Feeding MS resulted in lower environmental impacts than applying N even after taking into account the land to grow the maize for silage. Based on 2007/08 prices, typical NZ sheep and beef farms were making a financial loss and neither method of intensification increased profitability with the exception of small annual applications of N, especially to the 75% hill farm. These small annual additions of N fertiliser (<50 kg N/ha/yr applied in autumn and late winter) resulted in only small increases in annual N leaching (from 11 to 14 kg N/ha) and GHG emissions (from 3280 to 4000 kg CO₂ equivalents/ha). Limited N applications were particularly beneficial to 75% hill farms because small increases in winter carrying capacity resulted in relatively large increases in the utilisation of pasture growth during spring and summer than the 25% hill farms. Intensification by incorporating a beef feedlot reduced environmental emissions per kg of beef produced but considerably decreased profitability due to higher capital, depreciation and labour costs. The lower land-use capability farm type (75% hill) was able to intensify beef production to a proportionally greater extent than the higher land-use capability farm (25% hill) because of greater potential to increase pasture utilisation associated with a lower initial farming intensity and inherent constraints in the pattern of pasture supply.     

Short-term effects of nitrogen on methane oxidation in soils

 The short-term effects of N addition on CH₄ oxidation were studied in two soils. Both sites are unfertilized, one has been under long-term arable rotation, the other is a grassland that has been cut for hay for the past 125 years. The sites showed clear differences in their capacity to oxidise CH₄, the arable soil oxidised CH₄ at a rate of 0.013 μg CH₄ kg^–1 h^–1 and the grassland soil approximately an order of magnitude quicker. In both sites the addition of (NH₄)₂SO₄ caused an immediate reduction in the rate of atmospheric CH₄ oxidation approximately in inverse proportion to the amount of NH₄ ⁺ added. The addition of KNO₃ caused no change in the rate of CH₄ oxidation in the arable soil, but in the grassland soil after 9 days the rate of CH₄ oxidation had decreased from 0.22 μg CH₄ kg^–1 h^–1 to 0.13 μg CH₄ kg^–1 h^–1 in soil treated with the equivalent of 192 kg N ha^–1. A ¹⁵N isotopic dilution technique was used to investigate the role of nitrifiers in regulating CH₄ oxidation. The arable soil showed a low rate of gross N mineralisation (0.67 mg N kg^–1 day^–1), but a relatively high proportion of the mineralised N was nitrified. The grassland soil had a high rate of gross N mineralisation (18.28 mg N kg^–1 day^–1), but negligible nitrification activity. It is hypothesised that since there was virtually no nitrification in the grassland soil then CH₄ oxidation at this site must be methanotroph mediated. Received: 31 October 1997     

有机肥对水稻根际土壤中微生物和酶活性的影响

利用根际箱在红壤上研究了有机肥对水稻根际有效磷、根际微生物和土壤酶活性的影响。试验结果表明,有机肥明显地提高水稻根际和非根际土壤真菌、放线菌和细菌的数量及土壤有效磷的含量。根际土壤各类微生物的数量大于非根际土壤,表现出明显的根际效应。施用有机肥使根际效应增加,其效应为细菌 放线菌 真菌。有机肥还明显地促进水稻根际无机磷溶解菌和有机磷分解数量以及磷酸酶和脲酶的活性,同时对水稻根际土壤磷转化速率有明显的提高,从而加速了土壤养分的转化。     

Fractional extraction of compounds from grape seeds by supercritical fluid extraction and analysis for antimicrobial and agrochemical activities

White grape seeds were subjected to sequential supercritical fluid extraction. By increasing the polarity of the supercritical fluid using methanol as a modifier of CO(2), it was possible to fractionate the extracted compounds. Two fractions were obtained; the first, which was obtained with pure CO(2), contained mainly fatty acids, aliphatic aldehydes, and sterols. The second fraction, obtained with methanol-modified CO(2), had phenolic compounds, mainly catechin, epicatechin, and gallic acid. The fractions were bioassayed. Antimicrobial activities were checked on human pathogens, and a high degree of activity was obtained with the lipophilic fraction. Agrochemical activities on phytopathogenic fungi and activities on the etiolated wheat coleoptile bioassay were also checked. The more polar fraction was active in the latter bioassay.