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1.
High-temperature stress during the grain-filling stage reduces grain quality of rice, and this is a serious problem in Japan, especially in the Kyushu region. To solve this problem, various heat-tolerant cultivars have been bred, such as ‘Nikomaru’, ‘Kumasannochikara’, ‘Genkitsukushi’, ‘Sagabiyori’, and ‘Otentosodachi’. When cultivated under high temperature after flowering, these heat-tolerant cultivars had lower percentages of chalky grains than in the heat-sensitive cultivar ‘Hinohikari’. All the heat-tolerant cultivars markedly decreased the nonstructural carbohydrate content in the stem under the high temperature compared to control condition during early grain-filling stage, which is considered to be a common trait of heat tolerance. Notably, ‘Sagabiyori’, ‘Genkitsukushi’, and ‘Nikomaru’ maintained a nucellar epidermis at 17 days after flowering (DAF) under high temperature, whereas the nucellar epidermis disappeared in ‘Hinohikari’. In addition, the expression of AGPS2b, thought to be a rate-limiting enzyme in starch synthesis, in ‘Kumasannochikara’, ‘Otentosodachi’, and ‘Nikomaru’ did not decrease under high temperature, whereas ‘Hinohikari’, ‘Sagabiyori’, and ‘Genkitsukushi’ could not maintain expression of the gene at 17 DAF. Moreover, the expression of Amy3E, a starch-degradation-related gene considered to induce grain chalkiness, in ‘Kumasannochikara’ at 17 DAF was not increased by high temperature. These results suggest that the heat-stress-tolerant cultivars have various mechanisms for dealing with high-temperature stress.  相似文献   

2.
《Plant Production Science》2013,16(4):359-364
Abstract

Our objective was to clarify whether rice cultivars with a higher grain dry-matter increase rate (GIR) under elevated temperature condition show a higher percentage of milky white rice kernels (MWK). The rate of MWK judged using a rice-quality selector significantly varied with the cultivar and experimental year. The spikes of the cultivars detached 5–7 days after heading were solution-cultured with an adequate nutrient supply for one week at 25, 28 and 33ºC. GIR was overall the highest at 28ºC, and GIR at this temperature was considered to reflect the potential GIR in all the grains tested. There was a close correlation between the rate of MWK and the GIR at 28ºC under field conditions when temperatures during the grain-filling period were approximately over 25ºC. It was suggested that cultivars with a higher potential GIR under elevated temperature conditions have a higher risk of the formation of MWK.  相似文献   

3.
《Plant Production Science》2013,16(4):233-239
Summary

Photosynthetic ability in terms of CO2 exchange rate and leaf area, dry matter accumulation (dry weight) and other important growth components along with yield and yield contributing characters in two F1 hybrids of Akebono × Chiyonishiki (A × C) and Zenith × Akebono (Z × A) were studied. The photosynthetic rate at the flowering stage was lower than that at the panicle initiation stage in all the inbred parent cultivars and F1 hybrids. Heterosis in photosynthetic rate was higher at the panicle initiation stage than that at the flowering stage. Pre-anthesis leaf area in the F1 hybrid was significantly larger than that in the parent cultivars. However, the post- anthesis decline in leaf area was more rapid in the F1 hybrids than in the parent cultivars and its magnitude was the highest in the F1 hybrid of Z × A which was tall having long and curved panicles. Pre-anthesis dry matter accumulation in both hybrids was significantly higher in the F1 plants than the parental cultivars, but post-anthesis dry matter accumulation in the F1 hybrid was lower than the mid-parental value in Z × A. The degree of heterosis in grain yield varied with the hybrid combination, an average heterosis being 1.03. Heterosis in grain yield was closely associated with heterosis in harvest index.  相似文献   

4.
《Plant Production Science》2013,16(2):160-168
Abstract

The resistance to high-temperature stress and the structural appearance of the imperfect grains caused by a high temperature at the ripening stage were studied using 13 selected cultivars of rice. High temperature treatment (daily maximum temperature range, 32-40°C) given from the 4th day after heading caused the decrease in panicle weight in all of the cultivars examined. The number of empty grains in the upper and lower parts of a panicle was increased by the high temperature in 10 cultivars. Cultivars KRN, Citanduy, Belle patna and BPB were tolerant to the high-temperature treatment at the ripening stage, and cvs. Koshihikari, Sanlicun, Tainung 67, Yamada-nishiki and Lady Wright were sensitive. Light microscopic observation showed that, the whole endosperm was covered with a nucellar epidermis (NE) under both high and natural temperature (26-31°C) conditions at the first week after heading (WAH). Under high-temperature conditions the NE degenerated earlier than under natural temperature conditions. Scanning electron microscopic observation showed that, the endosperm cells of the seeds with a specific gravity (s.g.) of higher than 1.06 had large amyloplasts filled with starch granules. However, the endosperm cells of seeds with a s.g. of 1.00-1.06 had many small amyloplasts containing small single starch granules and had numerous spaces among the amyloplasts. In the endosperm cells at the dorsal side of imperfect grain, layered structures showing progressive decomposition of starch granules were observed.  相似文献   

5.
《Plant Production Science》2013,16(2):111-117
Abstract

We examined the association of assimilate supply in the occurrence of milky white kernels in three cultivars with different percentages of milky white kernels in the field condition: ‘Hatsuboshi’, ‘Koshiibuki’ and ‘Koshihikari’. Five days after heading, the plants were placed in four controlled-environment chambers with either a high or low night temperature and elevated or normal [CO2] supply. Plants in each chamber were either defoliated with only flag leaf remaining, flag leaf and second leaf remaining or left intact (control). The percentage of each type of chalky kernel was examined. The percentage of milky white kernels was increased by defoliation and decreased by elevated [CO2], associated with assimilate supply. No association was observed between assimilate supply and white back or basal white kernels. The percentage of milky white kernels was negatively correlated with assimilate supply at a high night temperature in all cultivars. At a low night temperature, there was a clear threshold of assimilate supply, over which the percentage of milky white kernels was nearly zero. Cultivar differences were observed in the relation between the percentage of milky white kernels and assimilate supply. In conclusion, we found a varietal difference in the occurrence of milky white kernels in response to assimilate supply. In the cultivars used in this study, ‘Hatsuboshi’ was more sensitive to the low assimilate supply than ‘Koshihikari’.  相似文献   

6.
The evaluation of rice (Oryza sativa L.) cultivars assists breeders in identifying useful trait relationships and in selecting parents as donors of specific traits. This study was conducted to compare long-grain rice cultivars using genotype × trait (GT) biplot analysis and determine potential donors of traits related to grain yield and quality. Seventeen cultivars in the 2005 and 2006 Uniform Regional Rice Nursery in Beaumont, Texas, USA were analyzed for 20 traits using GT biplot analysis. The GT biplots showed the diversity among cultivars with regards to yield-related traits. Cultivars recommended as donor parents were: Trenasse, Spring, Presidio, and Cocodrie for high grain yield and head rice rate; Trenasse and Presidio for semi-dwarfness; Banks for tall plant height; Wells for high flag leaf area, panicle weight, and number and mass of filled grains per panicle; Hidalgo for high tiller density; Francis for high number of spikelets per panicle; Spring and Trenasse for short flowering duration; Cheniere for more days to heading and maturity and Spring for less days; and Spring and Hidalgo for high grain weight. Breeders can use these cultivars with specific traits to increase grain yield and quality.  相似文献   

7.
Foxtail millet grains usually contain carotenoids, which are yellow pigments that are important for human health. Yellow grains are preferred by distributors and consumers, and special cultivars and cultivation methods are desired for a stable supply of yellow millet. We investigated the level of pigment fluctuation in several foxtail millet accessions, including the yellow grain cultivar ‘Yuikogane’ from Iwate Prefecture, using high-performance liquid chromatography. Most yellow grains primarily contained xanthophylls, including approximately 1 mg/100 g lutein and 0.2 mg/100 g zeaxanthin. These pigments were rare in the bran and grain husks but were readily detected in polished grains, indicating that xanthophylls accumulate in the endosperm. We examined ‘Yuikogane’ to investigate the relationship between xanthophyll accumulation and grain ripening. During the ripening stage, xanthophyll levels gradually increased, but they rapidly decreased in response to over-ripening. Xanthophyll accumulation was estimated using a colorimetric assay of yellow pigmentation, which could be a useful method for determining the proper harvesting time for foxtail millet.  相似文献   

8.
《Plant Production Science》2013,16(4):409-419
Abstract

Understanding wheat (Triticum aestivum L.) response to high shoot/root temperature during the early growth stages is important for successful production in tropical and subtropical environments. This study examined the physiological response of wheat cultivars to high shoot and/or root temperatures during early growth stages. Three cultivars; Imam, Fang and Siete Cerros were grown in soil and hydroponically at three shoot/root temperatures (23/23, 23/35 and 35/35ºC for the soil experiment; and 22/22, 22/38 and 38/38ºC for the hydroponic experiment). Leaf dry weight and leaf area plant-1 were significantly decreased by high shoot/ root temperature (HS/HR, 35/35 and 38/38ºC) but was not affected by a normal shoot/high root temperature (NS/HR, 23/35 and 22/38ºC). The NS/HR (22/38ºC) and HS/HR (38/38ºC) treatments in the hydroponic experiment significantly decreased photosystem II quantum yield ( Φpsii), photosynthetic rate (Pn) and specific leaf area (SLA) compared with the normal shoot/normal root (NS/NR, 22/22ºC) temperature treatment. Chlorophyll accumulation was significantly decreased by NS/HR, but increased significantly by HS/HR in most of the measuring dates. The heat-tolerant cultivar, Fang, always had the highest chlorophyll content, Φpsii and Pn under all temperature treatments, while the heat-sensitive cultivar, Siete Cerros, always had the greatest reduction in these traits especially towards the end of the experiment. Imam and Fang responded to HS/HR in the hydroponic experiment by immediate and greater reductions in leaf dry weight, total leaf area and SLA during the first wk of the treatments compared with Siete Cerros. The response changed with the treatments duration such that Imam showed the least reduction and Siete Cerros was the most affected cultivar towards the end of the experiment. Thus, wheat cultivars differentially responded to high shoot/root temperature by reducing the leaf weight and area and hence accumulating more chlorophyll in the diminished leaves. The failure to undergo such changes led to significantly lower chlorophyll accumulation, Φpsii and Pn under high root temperature.  相似文献   

9.
This study was conducted to clarify the relationship between the number of pollen grains per anther and spikelet fertility under low temperature conditions in the rice cultivars and lines including lines with quantitative trait loci (QTL) for cold tolerance, adapted to the Tohoku region of northern Japan. Cold-water treatment decreased anther length, the number of pollen grains per anther, and spikelet fertility in all cultivars and lines. The number of pollen grains was proportional to anther length in all cultivars and lines and under all temperatures. Spikelet fertility decreased with decreasing the number of pollen grains in cold-water treatments at 18.5 and 19.3?°C. ‘Ouu 415’, with the qLTB3 QTL for cold tolerance, had 28% more pollen grains and 9% higher spikelet fertility than the recurrent parent, ‘Hitomebore’, in the 18.5?°C cold-water treatment, suggesting that qLTB3 increased both parameters. Lines with the qCTB8 QTL for cold tolerance had significantly more pollen grains in two of the three years and significantly higher spikelet fertility in all three years in the 19.3?°C cold-water treatment, suggesting that qCTB8 reinforced cold tolerance. Ctb1, a proposed cold-tolerance QTL, had no effect on the number of pollen grains or spikelet fertility. In conclusion, the cultivars and lines with more pollen grains had a higher cold tolerance. Some of QTLs were inferred to increase the number of pollen grains and reinforce cold tolerance.  相似文献   

10.
《Plant Production Science》2013,16(3):307-315
Abstract

The effects of elevated carbon dioxide concentration ([CO2]) on silica deposition on husk epidermis of rice (Oryza sativa L. cv. Akitakomachi) during the flowering stage were investigated in this study. The study was motivated by the concept that the rice yield maybe affected by global warming as a result of elevated [CO2] environment since sterility of rice is related to the panicle silica content that influences transpiration, and elevated [CO2] could affect plant transpiration. Silica deposition analysis was focused on the flowering stage of the rice crop grown hydroponically under two [CO2] conditions: 350 μmol mol-1 (ambient) and 700 μmol mol-1 (elevated). Silica deposition on the husk epidermis from three parts of the panicle at four flowering stages were examined using a scanning electron microscope (SEM) combined with an energy dispersive X-ray microanalyzer (EDX). The results demonstrated that elevated [CO2] significantly suppressed silica deposition on the husk epidermis at the lower part of the panicle, and at the early flowering stage when 1/3 of the panicle emerged from the leaf sheath. In the transverse section analysis of the husk, silica deposition on the husk epidermis under elevated [CO2] was less than that under ambient [CO2] at the late flowering stage. The less silica deposition observed on the husks at the late flowering stage under elevated [CO2] might be related to the suppressed transpiration from the panicle by elevated [CO2] found in a previous study.  相似文献   

11.
《Plant Production Science》2013,16(4):455-463
Abstract

Abstract: We investigated the effects of soaking temperature and duration on the germinability of seeds of rice (Oryza sativa L., cv. Koganemochi, Gohyakumangoku, and Koshihikari) that had been stored for a long period. The germinability of the seeds soaked at 5ºC for 5 d was markedly lower than that of seeds soaked at 12ºC for 5 d. The germinability of the seeds soaked at 5ºC for 24 hr was not increased by subsequent soaking at 12ºC for 4 d. On the other hand, the germinability of the seeds soaked either at 12ºC for 24 hr or at 30ºC for 80 min was similar to that of seeds soaked at 12ºC for 5 d, even when followed by treatment at 5ºC. Thus, the soaking temperature during the first 24 hr was most important for the germination of rice seeds that had been stored for a long period. Western blotting analysis revealed characteristic expression patterns of α-amylase isoforms in cultivars correlating with the germinability after soaking at a low-temperature.  相似文献   

12.
《Plant Production Science》2013,16(3):203-210
Summary

Generally F1 hybrids from crosses between japonica and indica rice show variable degrees of sterility. Previous studies revealed that among the indica rice, the Aus type has sexual affinity with japonica cultivars giving higher fertility in F1 hybrids. Therefore, we made an effort to obtain higher grain yield by producing F1 hybrids between japonica and Aus-type indica. A field experiment was conducted to investigate the heterosis in these F1 hybrids for dry matter accumulation, spikelet fertility, yield and yield attributes, to find cross combinations with higher grain yield, and examined the relationships of grain yield with some agronomic characters. F1 hybrids flowered earlier than their parent cultivars. Heterosis for dry matter accumulation was positive at the panicle initiation stage, at heading and at maturity. The average heterosis for number of panicles, grain and straw yield per plant, number of spikelets per panicle and 1000-grain weight was positive. A few F1 hybrids showed positive heterosis for number of filled grains per panicle, spikelet fertility and harvest index; but the average heterosis for these traits was negative. Among the yield components, a higher number of panicles per plant and higher number of spikelet per panicle contributed to higher grain yield in F1 hybrids. A significant and positive relationship existed between spikelet fertility and grain yield per plant. The higher grain yield was attributed to higher dry matter production rather than higher harvest index in F1 hybrids, although low spikelet fertility limited yield potential in some F1 hybrids.  相似文献   

13.
《Plant Production Science》2013,16(2):132-140
Abstract

The effects of temperature during the ripening period on digestible protein contents of the rice grains of a seed-protein mutant rice cultivar LGCsoft were examined. The plants were grown under a natural condition until the booting stage, and then in temperature-controlled greenhouses set at 24.0ºC, 28.0ºC, and 30.6ºC (mean temperature). The protein compositions and the protein contents of the rice grains were analyzed quantitatively. The protein compositions in the LGCsoft grains varied with the temperature condition. The ratio of the digestible to total protein was higher in high-temperature conditions, and that of difficult-to-digest proteins, especially 13 kDa prolamin was lower in high-temperature conditions. The protein compositions in a normal-type cultivar Nihonmasari, which was the original cultivar of LGCsoft also varied with the temperature. However, the effect of temperature on the ratio of the digestible to total protein was larger in LGCsoft than in Nihonmasari. The ratios of the digestible protein in the grains under 24.0ºC and 30.6ºC conditions were 74.3% and 81.3%, respectively, in Nihonmasari. On the other hand, they were 52.0% and 63.1%, respectively, in LGCsoft. In LGCsoft, the total protein content of grains was 70.6-72.5 mg g-1, and it was affected only slightly by temperature during the ripening period. Therefore, the digestible protein content of grains under 24.0ºC and 30.6ºC conditions was 36.7 mg g-1 and 45.7 mg g-1, respectively, in LGC soft. It was clarified that the digestible protein content was higher at elevated temperatures because of the increased ratio of digestible to total protein.  相似文献   

14.
Fourteen commercial hybrid cultivars of sorghum grain were examined for physical characteristics before and after being milled by abrasion. Milling to 10% total loss in weight resulted in the pigments in the pericarp being effectively removed but colour spots on the hilar and germ remained on most cultivars and the testa was exposed on some cultivars. Milling showed that the cultivars were of varying degrees of hardness but all gave >80% yield of unbroken kernels with the germ attached. The milled grains were boiled like rice but the cooking time was high for all cultivars (range 57–64 min) although the water uptake and swelling of the cooked grain was satisfactory and the solids lost during cooking was low.  相似文献   

15.
以34个水稻品种或品系为试材,对产量、产量构成因素、穗部性状、叶部性状等进行了研究。结果表明:品种间产量差异极显著,辽盐188、龙盘5号、沈稻9号、辽盐158、沈稻9810等产量较高。产量与成粒率呈显著的正相关,与每穗秕粒数呈显著的负相关,与倒2叶长、倒3叶长也呈显著的负相关。  相似文献   

16.
《Plant Production Science》2013,16(3):217-225
Abstract

Genetic variation in the growth response to temperature is a basis for developing adaptation measures to global warming, but evaluation of cultivars for the temperature responses may depend on other environmental factors such as light. In this study, we tested the growth responses of 18 diverse rice cultivars to constant day/night temperature of 25, 28, 31 and 34ºC in artificially-lit growth chambers (ALC) in Wagga Wagga (7.8 MJ m-2 d-1), and in naturally-lit chambers (NLC) in Yanco (25 and 28ºC and 13.4 MJ m-2 d-1; 31 and 34ºC and 11.5 MJ m-2 d-1), both in NSW, Australia. There was a significant interaction between temperature and chamber type for total shoot and panicle biomass; total shoot biomass was largest at 31ºC in ALC, and at 25 and 28ºC in NLC. From the average of all temperatures, the total shoot biomass declined by 29.5% in plants grown in ALC compared with those grown in NLC. Importantly, cultivar performance in ALC was similar to that in NLC at these temperatures, as evidenced by the highly significant correlation in total shoot biomass between ALC and NLC. Among 18 cultivars, IR64, IR72, N22, Vandana, Takanari and Koshihikari commonly produced a larger total shoot biomass under higher temperature conditions. Leaf area at earlier measurement date was highly correlated with the final total shoot biomass at the higher temperature more than specific leaf area.  相似文献   

17.
Two winter wheat (Triticum aestivum L.) cultivars, namely Jimai22 (JM22) and Zhouyuan9369 (ZY9369), were used to study the effects of a new irrigation policy, supplemental irrigation (SI) based on soil moisture levels, photosynthesis, dry matter accumulation, and remobilization from 2009 to 2011 in Northern China. Two SI treatments were designed based on relative soil moisture contents in the 0–140 cm soil layer: (1) the target soil relative water contents were 75% of field capacity (FC) at jointing and 65% of FC at anthesis (W1), 75% and 70% (W2) in 2009–2010, and (2) the target soil relative water contents were 75% at jointing and 75% at anthesis (W1′), 75% and 80% (W2′) in 2010–2011. Rain-fed treatment (W0) was used as control. Results showed that SI significantly improved the biomass, grain yield and water use efficiency (WUE) of both wheat cultivars. The biomass and grain yield of W1 and W1’ treatments were higher than those of others. The net photosynthetic rate, the actual photochemical efficiency of flag leaf, the accumulation of dry matter, and its remobilization from the vegetative parts to the grains after anthesis in W1 and W1’ treatments were significantly higher than in the other treatments. By contrast, the WUE and irrigation efficiency of W2 and W2’ were significantly lower than those of W1 and W1’. Under the experimental conditions, ‘JM22’ showed higher photosynthetic rate in the last stage of grain filling, more spike number per ha, more kernels per spike, higher 1000-kernels weight and eventually higher WUE than ‘ZY9369’.  相似文献   

18.
《Plant Production Science》2013,16(2):146-153
Abstract

The germination and emergence of soybean [Glycine max (L.) Merr.] can be adversely affected by the presence of excessive water as a result of continuous rainfall. The pre-germination flooding-tolerant cultivars can be tolerant to hypoxia in the flooding field. The objective of this study was to clarify the relationship between germination under hypoxia at different temperatures and pre-germination flooding tolerance. Seeds of 6 soybean cultivars were subjected to 5 oxygen concentrations and 3 temperatures. Seeds of all 6 cultivars hardly germinated under an oxygen concentration of 20 mL L–1, but germinated with increasing oxygen concentration regardless of temperature. The pre-germination flooding-tolerant cultivar ‘Peking’ exhibited poorer germination under hypoxia than the other cultivars. Seed coat of ‘Peking’ did not dehisce when seeds did not germinate under hypoxia regardless of temperature. The pre-germination flooding-susceptible cultivar ‘Nakasennari’ exhibited higher seed coat dehiscence, but the dehiscence mostly occurred on the seed surface rather than micropyle under hypoxia at 25°C and 30°C. Seven days after termination of 3-d hypoxia treatment at 30°C, the percentage of seedlings with root hairs and/or lateral roots relative to that after ambient oxygen treatment was maintained in ‘Peking’ but decreased in the other cultivars, especially in ‘Nakasennari’. Pre-germination flooding-tolerant cultivar, especially ‘Peking’, is characterized by a delay in germination processes under hypoxia, and exhibits vigorous germination after release from hypoxia.  相似文献   

19.
《Plant Production Science》2013,16(3):243-251
Abstract

Projected global warming is expected to increase the occurrence of heat-induced floret sterility (HIFS) in rice. However, there are few field-scale studies that could aid in predicting the potential risks to rice yield and developing countermeasures against yield losses. The aim of this study was to elucidate the factors that induce floret sterility under high temperature conditions during the flowering season in the field condition in China. Studies were conducted in irrigated paddy fields with the regional hybrid-rice cultivars grown in Jianghan Basin where air temperature is not so high during the flowering season but HIFS frequently occurs. The microclimate, panicle temperature, floret sterility, pollination, and size of dehiscence formed at the base of anthers were investigated. Significant losses in seed set were observed under the high temperature condition. Although the maximum atmospheric temperature was approximately 35ºC, the relative humidity was very high (around 70% at the time of maximum temperature), with low wind speeds, occasionally below 1 m s1. Under such conditions sunlit panicle temperature exceeded atmospheric temperature by as much as 4ºC. Moreover, the anthers of some cultivars exhibited short basal dehiscence, and the dehiscence length was positively correlated with the percentage of sufficiently pollinated florets (r=0.859, P<0.05, n=7) and with seed set (r=0.827, P<0.05, n=7) across the cultivars. The results suggest that the combination of hot, humid, and windless climatic conditions with short basal dehiscence of anthers induces HIFS in hybrid rice grown in this region.  相似文献   

20.
为明确不同采收期对油葵种子质量和品质的影响,本研究以67×早R、36×早R和早熟矮大头3个油葵材料为研究对象,于开花后30、35、42、47 d收获种子,对相同条件下晾干的种子进行活力相关指标和品质指标测定.结果表明,67×早R和早熟矮大头在开花后42 d收获的种子,活力较高;36×早R以开花后47 d收获的种子,活力...  相似文献   

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