scholarly journals Production of Hybrid Rice seeds using environment sensitive genic male sterile (EGMS) and basmati rice lines in Kenya

2019 ◽  
Author(s):  
Njiruh Paul Nthakanio ◽  
Kariuki Simon Njau
Keyword(s):  
High Temperature ◽  
Hybrid Rice ◽  
Male Gamete ◽  
Growth Conditions ◽  
Basmati Rice ◽  
Rice Seed ◽  
Male Sterile ◽  
Male Gametes ◽  
Rice Seeds ◽  
The Impact

AbstractPhotoperiod-sensitive genic male sterile rice (PGMS) lines IR-73827-23-76-15-7 S, IR-75589-31-27-8-33S referred to as P1 and P2, and IR-77271-42-25-4-36S, thermo-sensitive genic male sterile (TGMS) line referred to as T were obtained from International Rice research Institute. These lines, collectively known as environment genic male sterile lines, were sown under greenhouse growth conditions where temperatures were more than 34°C with an objective of inducing complete male gamete sterility in them. Results indicated that high temperature growth conditions induces complete male gamete sterility in both the PGMS and TGMS lines. The impact of this is that, it will be possible to produce pure basmati hybrid rice seed in the tropical regions without contamination with pure breed lines. The male sterile PGMS/TGMS were pollinated with pollen from basmati370 and 217 grown under natural conditions and some hybrid seeds were obtained. This shows that high temperature emasculated the male gametes but not female ones. The conclusion is that it is possible to induce complete male gamete sterility in PGMS and TGMS under greenhouse in tropical growth conditions, and to produce hybrid rice seeds. This makes basmati hybrid rice seed production in Kenya a viable venture.

scholarly journals Breeding of the Dormant Thermosensitive Genic Male-Sterile Lines of Early Rice to Overcome Pre-Harvest Sprouting of the Hybrid Seeds

Agronomy ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 191 ◽  
Author(s):  
Xiaoyu Chen ◽  
Yun Tian ◽  
Xiangyang Lu
Keyword(s):  
High Temperature ◽  
Seed Dormancy ◽  
Wild Rice ◽  
Seed Quality ◽  
Hybrid Rice ◽  
Oryza Rufipogon ◽  
Rice Seed ◽  
Hybrid Seed Production ◽  
Male Sterile ◽  
Early Rice

The pollen development of male-sterile lines should be conducted during the high temperature season to ensure the sterility of male-sterile line pollen and the safety of hybrid seed production in the breeding of thermosensitive genic male-sterile (TGMS) lines of early rice. However, the mature hybrid rice seeds are prone to pre-harvest sprouting (PHS) during hot, rainy days, which leads to the decrease of hybrid rice seed quality or a loss of utilization value. In this study, with an aim to bring a dormancy trait from the dormant genotype to the current low-dormant TGMS lines, a common wild rice “Chaling” (Oryza rufipogon), which has strong seed dormancy, a large black stigma, and a high exsertion rate, was hybridized with the early rice TGMS line “Zhu 1S,” which often exhibits PHS. After screening for early maturing and seed dormancy, the early rice “Yezao S” and “Yezhuzao S,” with the characteristic of seed dormancy, were selected. The critical temperature of high temperature sterility for these two male-sterile lines was below 23.5 °C. The stigma of “Yezao S” was black and its exsertion rate was 79.9%, while “Yezhuzao S” had a colorless stigma with an exsertion rate of 76.8%. The expression of the genes OsNCEDs in “Yezao S” and “Yezhuzao S” were significantly higher than that in “Zhu 1S” the 15th day after heading, and the abscisic acid (ABA) content was also higher than that of “Zhu 1S” the 20th day after heading. The results indicated that introducing the dormancy characteristics from wild rice “Chaling” into the early rice TGMS lines was an effective way to prevent PHS.

Effect of High Temperature Intermittent Drying on Rice Seed Viability and Vigor

2017 ◽  
Vol 13 (10) ◽  
Author(s):  
Pan Wang ◽  
Dong Li ◽  
Li-jun Wang ◽  
Benu Adhikari
Keyword(s):  
High Temperature ◽  
Ambient Temperature ◽  
Seed Viability ◽  
Seed Vigor ◽  
Drying Rate ◽  
Rice Seed ◽  
Rice Cultivars ◽  
Moisture Contents ◽  
Rice Seeds ◽  
Tempering Process

AbstractThis work aimed at determining whether high temperature intermittent drying followed by tempering at ambient temperature could preserve the seed viability and vigor.JaponicaandIndicarice seeds with 21.2 % and 22.6 % wet moisture contents (w.b.) were dried at 50 ºC and 60ºC for either 5, 10, 15 or 20 minutes, followed by tempering at 25ºC for 45 minutes. Each drying cycle was repeated until the rice seeds were dried to 12.0 % (w.b.). The drying rate was improved and the total in-dryer time was reduced in the intermittent drying when compared to continuous drying, due to the tempering process. The seed vigor was significantly reduced by intermittent drying at 60 °C with all exposure times, although the seed still kept the ability to germinate for both rice cultivars. The intermittent drying at 50 ºC for 5 minutes per drying cycle preserved the seed vigor ofJaponicarice well, while inIndicarice, the intermittent drying at 50 ºC up to 20 minutes could still be able to maintain the seed vigor.

On the Formation of Intrinsic Defects in 4H-SiC by High Temperature Annealing Steps

2012 ◽  
Vol 717-720 ◽  
pp. 247-250 ◽  
Author(s):  
Bernd Zippelius ◽  
Jun Suda ◽  
Tsunenobu Kimoto
Keyword(s):  
High Temperature ◽  
Carrier Lifetime ◽  
Growth Conditions ◽  
Device Fabrication ◽  
Defect Concentration ◽  
Epitaxial Layers ◽  
High Temperature Annealing ◽  
Intrinsic Defects ◽  
Initial Defect ◽  
The Impact

In this paper the impact of high temperature annealing on the formation of intrinsic defects in 4H-SiC such as Z1/2 and EH6/7 was examined. Therefore, three epitaxial layers with various initial concentrations of the Z1/2- and EH6/7-centers (1011 – 1013 cm-3) were investigated. It turns out that depending on the initial defect concentration the high temperature annealing leads to a monotone increase of the Z1/2- and EH6/7-concentration in a temperature range from 1600 to 1750°C. For a defined temperature above these values, the resulting defect concentration is independent of the sample’s initial values. Beside the growth conditions themselves such as C/Si ratio the thermal post-growth processing has a severe impact on the carrier lifetime which must be taken into account during device fabrication.

scholarly journals The first study on the impact of osmolytes in whole cells of high temperature-adapted microorganisms

Soft Matter ◽  
2019 ◽  
Vol 15 (41) ◽  
pp. 8381-8391 ◽  
Author(s):  
Marta Salvador-Castell ◽  
Maksym Golub ◽  
Nicolas Martinez ◽  
Jacques Ollivier ◽  
Judith Peters ◽  
...  
Keyword(s):  
High Temperature ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Structural Rearrangements ◽  
Whole Cells ◽  
The Impact

The presence of the osmolyte mannosylglycerate in alive cells of Thermococcus barophilus, a hyperthermophile and piezophile, limits the structural rearrangements of its proteome under the archaeon optimal growth conditions, i.e. 358 K and 40 MPa.

Factors encouraging complete adoption of agricultural technologies

2018 ◽  
Vol 8 (2) ◽  
pp. 270-287 ◽  
Author(s):  
Varsha Khandker ◽  
Indrajit Thakurata
Keyword(s):  
Hybrid Rice ◽  
Geographical Location ◽  
Rice Cultivation ◽  
Agricultural Technologies ◽  
Indian States ◽  
Climatic Zones ◽  
Content Type ◽  
Rice Seeds ◽  
Adoption Level ◽  
The Impact

Purpose Hybrid rice is considered as one of the technologies having the potential to push the production frontier to meet the growing demand for rice in India. The technology was introduced in India in 1994 but is yet to see widespread adoption. The purpose of this paper is to identify the factors that influence the partial/complete adoption of hybrid rice technology by the farmers in India. This study also assesses the factors behind difference in the share of land allocated to hybrid rice cultivation by farmers. Design/methodology/approach The study employs a Tobit model to evaluate the impact of factors related to technology, farmer, farm and geographical location on the decision to adopt hybrid rice. Data for this study are compiled from surveys of 441 hybrid rice growing farmers across 3 Indian states conducted during 2012-2013. Findings The paper finds that farmers with smaller landholdings, higher education and higher experience of growing hybrid rice are more likely to be complete adopters. Farmers reporting good demand for hybrid rice output and availability of subsidy on hybrid rice seeds also have higher probability of being complete adopters. However, the availability of hybrid rice seeds in government outlets and cultivating multiple kharif crops are negatively related to the extent of hybrid rice adoption. The results suggest insignificant impact of age, family size, ownership of cattle and machinery on the adoption level of hybrid rice by the farmers. Research limitations/implications Although the sample for this study has been collected from three states with different agro-climatic zones and productivity, the results cannot be generalized for other states. Originality/value There is a great potential to increase the area under hybrid rice cultivation in India. This study is one of the first attempts to look at the adoption levels of hybrid rice in India and determine the factors which might be hindering the complete adoption of the technology. Focusing on the factors positively related to complete adoption can help in enhancing the area under hybrid rice and similar approach can be used for other new agricultural technologies in the developing country context.

scholarly journals Characteristics of Fertility Transition Response to the Cumulative Effective Low Temperature in a Two-Line Male Sterile Rice Cultivar

Rice ◽  
2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Linxuan Wu ◽  
Huazhen Rong ◽  
Chun Chen ◽  
Xin Lin ◽  
Jiafeng Wang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Seed Production ◽  
Pollen Fertility ◽  
Hybrid Rice ◽  
Fertility Transition ◽  
Day Length ◽  
Sensitive Period ◽  
Rice Seed ◽  
Night Temperature ◽  
Male Sterile

Abstract Background Photo-thermo-sensitive genic male sterile (PTGMS) rice (Oryza sativa L.) is usually considered two-line male sterile rice because of its dual-purpose in two-line hybrid rice system: under short days and low temperatures, it is fertile and used for self-propagation, but under long days and high temperatures, it is sterile and used for hybrid seed production. Therefore, photoperiod and temperature conditions are extremely important for the fertility transition of two-line male sterile rice. In recent years, there have been frequent occurrences of abnormally low-temperature (ALT) resulting in failure of two-line hybrid rice seed production. The daily average temperature (DAT) during ALT events is sometimes higher than the critical sterility-inducing temperature (CSIT) of two-line male sterile rice, of which the night temperature is lower than the CSIT. DAT has been traditionally used as the single indicator of pollen fertility transition, but it is unknown why the fertility of two-line male sterile rice in seed production restored fertility under ALT conditions. Results For Hang93S (H93S), a newly released PTGMS line, we hypothesized fertility transition is determined mainly by the cumulative effective low temperature (ELT) and only a certain duration of low temperature is required every day during the fertility-sensitive period. This study simulated ALTs where the DAT was higher than the CSIT while some segments of night temperature were lower than the CSIT. The results showed H93S exhibited a fertility transition to varying degrees. Moreover, fertility was restored under simulated ALT conditions and pollen fertility increased with increasing cumulative ELT, indicating that the fertility transition was affected primarily by the cumulative ELT. Results also indicated that pollen fertility increased as the number of treatment days increased. Conclusions The fertility transition is caused mainly by the cumulative ELT. In two-line male sterile rice breeding, the effects of day length, ALT at night, and continuous response days should be considered together. The present study provides new insight into fertility transition so breeders can more effectively utilize the two-line male sterile rice, H93S, in breeding programs.

scholarly journals Application of Invigoration Technique in Order to Improve Seed

2020 ◽  
Vol 39 (2) ◽  
pp. 96
Author(s):  
Mira Landep Widiastuti ◽  
Sri Wahyuni
Keyword(s):  
Hybrid Rice ◽  
Growth Yield ◽  
Seed Vigor ◽  
Production Costs ◽  
Yield Reduction ◽  
Rice Seed ◽  
Hormonal Priming ◽  
Rice Seeds ◽  
On Farm ◽  
Priming Technique

<p>Seed is a component of production that contributes to increasing the national rice production. The use of low-quality seeds compared with production costs, non-uniform plant growth, yield reduction, and yield quality. One effort to improve the quality of seed vigor is through invigoration treatment. Invigoration technique among other hydration, thermal treatment, and coating. The hydration method is a water absorption system in seeds. Uncontrolled absorption (hydro-priming), by soaking and drying the seeds, hardening, on-farm priming, soaking for a certain period. The controlled system (osmo-priming) by immersing in osmotic solution, osmo-hardening (integration of hardening and osmo-priming), matri-priming with moist solid media, humidifications (with high humidity), and hormonal priming (with hormones. The second method is by temperature treatment, including by cooling and heating. The third technique is the coating treatment, namely coating the seeds. Hydration system hydro-priming for 30 hours can break seed dormancy with normal germination capacity of 91.3-99.3% in Memberamo, Cipunagara, and Maros varieties. The hardening technique is effective in increasing the germination of hybrid rice seeds for 12 hours with 2 cycles and for 24 hours with one cycle. The osmo-priming technique of soaking seeds in a 10 ppm GA3 solution or a mixture of 10 ppm GA3 + 15 ppm kinetin was effective in increasing the vigor of hybrid rice seeds. The matri-priming technique with rubbing ash as a medium plus the addition of 50 µ m GA3 was effective in breaking dormancy of the Membramo, Cipunagara, and Maros varieties of rice. It is can be applied, especially by small farmers.</p><p>Keywords: Rice, seed, invigoration, quality</p><p> </p><p><strong>Abstrak</strong></p><p><strong>PENERAPAN TEKNIK INVIGORASI DALAM MENINGKATKAN VIGOR BENIH PADI </strong></p><p>Benih merupakan komponen budi daya yang berkontribusi dalam meningkatkan produksi padi nasional. Penggunaan benih bermutu rendah berpengaruh terhadap penambahan biaya produksi, pertumbuhan tanaman tidak seragam, dan penurunan hasil dan mutu hasil. Salah satu upaya untuk meningkatkan mutu benih dari aspek vigor yang rendah adalah melalui perlakuan invigorasi. Teknik invigorasi dibagi menjadi tiga metode, yaitu hidrasi, perlakuan suhu, dan pelapisan (coating). Metode hidrasi merupakan sistem penyerapan air yang dapat terjadi pada benih. Penyerapan tidak terkontrol (hydro-priming) yaitu dengan merendam dan mengeringkan benih, pengerasan (hardening), on-farm priming yaitu merendam dalam jangka waktu tertentu. Sedangkan terkontrol (osmo-priming) dengan merendam pada larutan osmotik, osmo-hardening (integrasi hardening dan osmo-priming), matripriming dengan media padat lembab, humidifications (dengan kelembaban tinggi), dan hormonal priming (dengan hormon). Metode kedua adalah dengan perlakuan suhu, diantaranya dengan pendinginan dan pemanasan. Teknik ketiga adalah dengan perlakuan coating yaitu melapisi benih. Sistem hidrasi hydropriming selama 30 jam dapat mematahkan dormansi benih dengan daya kecambah normal 91,3-99,3% pada varietas Memberamo, Cipunagara, dan Maros. Teknik hardening efektif meningkatkan daya berkecambah benih padi hibrida selama 12 jam dengan dua siklus dan selama 24 jam dengan satu siklus. Teknik osmo-priming perendaman benih dalam larutan GA3 10 ppm atau larutan campuran GA3 10 ppm + kinetin 15 ppm efektif meningkatkan vigor benih padi hibrida. Teknik matri-priming dengan abu gosok sebagai media plus penambahan GA3 50 µm efektif mematahkan dormansi padi varietas Membramo, Cipunagara, dan Maros. Teknik invigorasi tersebut dapat diterapkan, khususnya oleh petani dengan skala produksi kecil.</p><p>Kata kunci: Padi, benih, invigorasi, mutu</p>

scholarly journals Identification of Metabolomic Biomarkers of Seed Vigor and Aging in Hybrid Rice

2021 ◽  
Author(s):  
Bingxian Chen ◽  
Jiadong Gao ◽  
Shijuan Yan ◽  
Yinxin Zhang ◽  
Qi Zhang ◽  
...  
Keyword(s):  
Gluconic Acid ◽  
Seed Quality ◽  
Hybrid Rice ◽  
Germination Percentage ◽  
Seed Vigor ◽  
Primary Metabolism ◽  
Rice Seed ◽  
Seed Aging ◽  
Rice Seeds ◽  
Metabolite Markers

Abstract BackgroundSeed deterioration during rice seed storage will lead to seed vigor loss, which adversely affects agricultural production, the long-term preservation of germplasm resources, and the conservation of species diversity. However, the mechanisms underlying seed vigor maintenance remain largely unknown. ResultsIn this study, 16 hybrid rice combinations were selected from four sterile lines and four restorer lines. Following artificial aging and natural aging treatments, the metabolite markers that could accurately reflect the aging degree of the hybrid rice seeds were identified based on the germination percentage and metabolomics analysis by gas chromatography-mass spectrometry. Significantly differences in the degree of seed deterioration were observed among the 16 hybrid rice combinations tested, with each restorer and sterile lines after storage having the different germination percentage. The hybrid rice combination with the storage-resistant restorer line Guanghui122 exhibited the highest germination percentage under both natural and artificial storage. A total of 89 metabolic peaks and 56 metabolites were identified, most of which were related to primary metabolism. Interestingly, the content of galactose, gluconic acid, fructose and glycerol in the seeds increased significantly during the aging process. Absolute quantification indicated that galactose and gluconic acid were very significantly negatively correlated with the germination percentage of the seeds under the different aging treatments. The galactose content was significantly positively correlated with gluconic acid content. Additionally, while the relative content of raffinose did not change much during storage, a significant positive correlation between raffinose and the germination rate of the artificially aged seeds before storage was detected.ConclusionBased on the metabolomics, metabolite markers which could accurately reflect the aging degree of hybrid rice seeds were identified. Galactose and gluconic acid were very significantly negatively correlated with the germination percentage of the seeds which suggested that these metabolites could constitute potential metabolic markers of seed aging. These findings are of great significance for the rapid and accurate evaluation of seed aging, the determination of seed quality, and the development of molecular breeding approaches for high-vigor rice seeds.

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