摘要 :
There is an urgent need for agricultural systems to intensify sustainably, increasing crop productivity, farmer livelihoods and soil health while using fewer resources. Crop perennialization, the conversion of especially annual gr...
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There is an urgent need for agricultural systems to intensify sustainably, increasing crop productivity, farmer livelihoods and soil health while using fewer resources. Crop perennialization, the conversion of especially annual grains to perennial forms, has shown such possibility. Here we report the successful breeding of perennial rice and assess its performance and potential. Domesticated, annual Asian rice (Oryza sativa) was hybridized with its perennial African relative Oryza longistaminata. From a single planting, irrigated perennial rice produced grain for eight consecutive harvests over four years, averaging 6.8 Mg ha(-1) harvest(-1) versus the 6.7 Mg of replanted annual rice, which required additional labour and seed. Four years of cropping with perennial rice resulted in soils accumulating 0.95 Mg ha(-1) yr(-1) organic carbon and 0.11 Mg ha(-1) yr(-1) nitrogen, along with increases in soil pH (0.3-0.4) and plant-available water capacity (7.2 mm). Perennial cultivars are strongly preferred by farmers; growing them saves 58.1% of labour and 49.2% of input costs in each regrowth cycle. In 2021, perennial rice was grown on 15,333 ha by 44,752 smallholder farmers in southern China. Suited to a broad range of frost-free environments between 40 degrees N and 40 degrees S, perennial rice is a step change with potential to improve livelihoods, enhance soil quality and inspire research on other perennial grains. The environmental and socioeconomic costs of annual crops challenge their sustainability. This study reports the successful breeding of perennial rice and assesses its benefits for yields, soil health and farm labour and income as well as its potential geographic range globally.
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摘要 :
Oryza longistaminata, a perennial wild species, is widely distributed in the African continent. It has strong tolerance to biotic and abiotic stresses, and high biomass production on poor soils. Chlorophyll biosynthesis is importa...
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Oryza longistaminata, a perennial wild species, is widely distributed in the African continent. It has strong tolerance to biotic and abiotic stresses, and high biomass production on poor soils. Chlorophyll biosynthesis is important for photosynthesis in rice. However, the chlorophyll biosynthesis and related gene profiles of O. longistaminata and its descendants remained unclear. Here, the F1 generation of O. sativa and O. longistaminata were obtained. Then, the comparative analysis morphology, anatomical structure, and transcriptional regulatory networks of chlorophyll biosynthesis were detected and analyzed. Results showed that the F1 generation has obvious long awn, similar with that of the male parent. The purple color of the long awn is different from that of the male parent. Microstructural results showed that the flag leaves of F1 have large mesophyll cell gaps in the upper- and lower-positions, small mesophyll cell gaps in the middle position, and more chloroplasts. Increased chlorophyll content was also observed in the F1 generation. In the lower-position flag leaves, the total chlorophyll contents of F1 were 1.55 and 1.5 times those of O. sativa and O. longistaminata, respectively. POR, MgCH and HEMA1 showed higher expression levels than the other related genes selected in the chlorophyll biosynthesis pathway. The HEMA1 expression level in the middle-position flag leaves of O. longistaminata was the highest, and it was 2.83 and 2.51 times that of O. sativa and F1, respectively. The expression level of DVR gene in lower-position flag leaves of F1 were 93.16% and 95.06% lower than those of O. sativa and O. longistaminata, respectively. This study provided a potential reference for studying the photosynthesis and heterosis utilization of O. longistaminata.
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In Kenya's rice-growing areas, Basmati varieties have been produced in monoculture since the late 1980s. This has resulted in the breakdown of the resistance (R) gene-mediated response of the local Basmati varieties to blast disea...
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In Kenya's rice-growing areas, Basmati varieties have been produced in monoculture since the late 1980s. This has resulted in the breakdown of the resistance (R) gene-mediated response of the local Basmati varieties to blast disease caused by Pyricularia oryzae. To improve blast resistance in Kenyan Basmati varieties, continuous identification of R genes and suitable breeding materials for Basmati are necessary. Longistaminata chromosome segment introgression lines (LCSILs) with the Kernel Basmati genetic background, developed using a rice line called potential low-input adaptable-1 (pLIA-1) derived from a cross between Taichung 65 (T65) (a rice variety in the Japonica Group) and O. longistaminata, are expected to contain useful blast R genes derived from O. longistaminata or T65. In this study, we investigated the genetic variation of blast R genes in LCSILs and their parents by using a new international differential system for designating blast races based on the gene-for-gene theory and molecular characterization using single nucleotide polymorphism (SNP) markers. LCSILs and their parents were classified into three groups—A, B1, and B2—based on reaction patterns to the standard differential blast isolates (SDBIs). Group A, including pLIA-1, showed the highest resistance in all groups, followed by groups B1 and B2. Kernel Basmati in group B1 was considered to possess Pik-p or Pi7(t), Pi19(t), and other unknown R genes. In addition to these R genes, LCSIL 6, 12, 27, 28, and 40, in group A, were determined to possess one of Pish, Piz-t, or both genes that confer resistance to the Kenyan blast races. These lines can be used for efficiently pyramiding blast R genes in the local Basmati varieties.
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Weedy rice have long been known, particularly in tropical areas, as the result, of introgressions between wild and cultivated forms. More recently, rice fields have been frequently invaded by new weedy forms in temperate regions w...
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Weedy rice have long been known, particularly in tropical areas, as the result, of introgressions between wild and cultivated forms. More recently, rice fields have been frequently invaded by new weedy forms in temperate regions where wild forms were never reported. These plants show many traits similar to true wild O. rufipogon (shattering, dormancy, awning, organ pigmentation). Their occurrence concerns many parts of the world practicing intensive rice-growing with direct seeding. Samples of weeds from Camargue have been analyzed with 15 microsatellite markers in comparison to a representative collection of 145 Asian rice varieties. Diversity of weedy rice is in agreement with the genetic structure of O. sativa mainly organized in two main groups of indica and japonica. Weeds from Camargue showed a greater diversity than Mediterranean varieties (temporate japonica) as well as the presence of original alleles or alleles more typical of indica varieties. Genetic structure of weed stands appeared more probably the consequence of a predominantly autonomous dynamics allowed by seed conservation and dissemination than the result of gene flow with varieties from which they are isolated by a much greater precocity,. These results suggested that distant crosses between indica and japonica varieties and their effect on genome structure and expression could be a relevant explanation to this "weediness" process.
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Проведено сравнительное исследование динамики активирования и компонентного состава амилаз и протеиназ в семенах риса, прор...
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Проведено сравнительное исследование динамики активирования и компонентного состава амилаз и протеиназ в семенах риса, прорастающих вусловиях аэрации и гипоксии. Установлено, что гипоксия индуцирует в зерновках образование α-амилазы, β-амилазы и анодной формы эндопротеиназы. Сделан вывод б важной физиологической роли ферментов деградации белка и крахмала в жизнеспособности семян и проростков риса в условиях недостатка кислорода.
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摘要 :
Изучалась динамика активности и изоферментного состава α-амилазы в суспензионной культуре щитка риса (Oryza sativa L.). Показано, чт...
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Изучалась динамика активности и изоферментного состава α-амилазы в суспензионной культуре щитка риса (Oryza sativa L.). Показано, что уровень активности фермента зависит от концентрации сахарозы в питательной среде, а также связан со стадиями роста клеток и содержанием в них растворимого белка. Нативным электрофорезом установлено, что резкое возрастание активности α-амилазы в условиях сахарозоистощенной среды происходит за счет индукции синтеза ее катодных изоферментов. Полученные результаты предполагают существование различных механизмов, участвующих в регуляции активности отдельных изоформ α-амилазы риса.
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There is much doubt as to whether, in fact, the combination of nitrogen and silicate fertilization can increase yield and post-harvest yield in rainfed rice. The objective of this study was to investigate the effect of silicate an...
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There is much doubt as to whether, in fact, the combination of nitrogen and silicate fertilization can increase yield and post-harvest yield in rainfed rice. The objective of this study was to investigate the effect of silicate and nitrogen fertilization on the development, quality, yield and post-harvest yield of rice cultivated in the rainfed environment. A field experiment was carried out in the 2014/2015 harvest in a 4 × 4 randomized block design with four replications. The first factor corresponded to the nitrogen doses (0; 50; 100 and 200 kg ha-1 of N), in the form of urea, and the second factor at silicon doses (0; 7.5; 15 and 30 kg ha-1 Si), in the form of calcium silicate. Si affected the chlorophyll content at 45 days after sowing (DAS) suggesting being important in floral differentiation. The increase in N doses caused higher levels of chlorophyll in rice leaves at 55, 65 and 85 DAS, regardless of whether they supplied Si. Plant height, number of tillers, weight of one thousand seeds, total grain yield and of whole grains were not influenced by the Si supply. However, Si doses reduced the yield of broken grains, thus reducing postharvest losses and, consequently, improving grain quality in the beneficiation process.
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The use of dark septate fungi (DSE) to promote plant growth can be beneficial to agriculture, and these organisms are important allies in the search for sustainable agriculture practices. This study investigates the contribution o...
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The use of dark septate fungi (DSE) to promote plant growth can be beneficial to agriculture, and these organisms are important allies in the search for sustainable agriculture practices. This study investigates the contribution of dark septate fungi to the absorption of nutrients by rice plants and their ensuing growth. Four dark septate fungi isolates that were identified by Internal transcribed spacer phylogeny were inoculated in rice seeds (Cv. Piauí). The resulting root colonization was estimated and the kinetic parameters V max and K m were calculated from the nitrate contents of the nutrient solution. The macronutrient levels in the shoots, and the NO 3 - -N, NH 4 + -N, free amino-N and soluble sugars in the roots, sheathes and leaves were measured. The rice roots were significantly colonized by all of the fungi, but in particular, isolate A103 increased the fresh and dry biomass of the shoots and the number of tillers per plant, amino-N, and soluble sugars as well as the N, P, K, Mg and S contents in comparison with the control treatment. When inoculated with isolates A103 and A101, the plants presented lower K m values, indicating affinity increases for NO 3 - -N absorption. Therefore, the A103 Pleosporales fungus presented the highest potential for the promotion of rice plant growth, increasing the tillering and nutrients uptake, especially N (due to an enhanced affinity for N uptake) and P.
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摘要 :Oryza diploid species comprise AA, BB, CC, EE, FF, and GG genome groups. Cultivated rice, O. sativa L. of the AA genome, has two subspecies, indica and japonica. These two subspecies are differentiated in many characteristics, suc...
展开Oryza diploid species comprise AA, BB, CC, EE, FF, and GG genome groups. Cultivated rice, O. sativa L. of the AA genome, has two subspecies, indica and japonica. These two subspecies are differentiated in many characteristics, such as the number of nucleolar sites, annual-perennial habitat and polymorphism of plastid DNA. Although many researchers accept that japonica must originate from O. rufipogon, the evolutionary route of indica remains unclear. A 69-bp deletion in ORF100 is useful to discriminate between indica and japonica cultivars and between O. nivara and O. rufipogon; furthermore, PSID sequences of O. sativa-O. rufipogon complex contain hyper-variable sites consisting of C and A mononucleotide repeats, which are useful to classify wild accessions and cultivars into the six subtypes of 6C7A and 7C6A (japonica and O. rufipogon), 6C8A and 7C7A (O. nivara), 8C8A and 9C7A (indica). The 69-bp deletion is shared with O. nivara (6C8A, 7C7A) and indica (8C8A, 9C7A) but the 8C8A subtype is found only in indica. To elucidate variations of plastid DNA in the genus Oryza and cytoplasmic origin of indica, we compared two plastid sequences, ORF100 (676 bp) and PSBZ (629 bp), in 40 accessions of 14 Oryza diploid species. Sequence comparison showed that FF and GG genome species were distantly related to AA genome species. Both BB and CC genome species were related with AA genome species but were mutually differentiated. An evolutionary trace of ORF100 and PSBZ sequences indicated that O. barthii might have a consensus sequence among all AA genome species. Both O. longistaminata and O. glumaepatula were highly related with O. barthii; the O. sativa-O. rufipogon complex showed more various polymorphisms than other AA genome species. The results of this study show that 8C8A and 9C7A subtypes of plastids in indica cultivars are differentiated from 6C8A and 7C7A subtypes in O. nivara, despite sharing the same deletion in ORF100. In addition, 6C7A and 7C6A subtypes in japonica cultivars and O. rufipogon share identical sequences in PSBZ but differentiate at two SNP sites in ORF100.
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摘要 :
Каллюсная и суспензионная культуры изолированного щитка риса (Oryza sativa L.) характеризовались высокой α-амилазной активностью. В...
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Каллюсная и суспензионная культуры изолированного щитка риса (Oryza sativa L.) характеризовались высокой α-амилазной активностью. Выделенный из суспензионной культуры фермент был электрофоретически гетерогенен. Группы изозимов α-амилазы имели различия по ряду свойств. Исследовалось влияние экзогенных фитогормонов АБК, ГК и растворов глюкозы разных концентраций на α-амилазную активность в растущей каллюсной ткани. Показано ингибирующее действие повышенной концентрации моносахарида на уровень активности фермента в клеточной культуре.
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