Mapping of a Major QTL, qHD6-SD Responsible for Days to heading Under Natural Short Day Conditions to Develop Rice Varieties adaptable to Tropical Regions

2021 ◽  
Vol 33 (2) ◽  
pp. 161-169
Author(s):  
Maurene Bombay ◽  
◽  
Sais-Beul Lee ◽  
Myrish Pacleb ◽  
Sumin Jo ◽  
...  
Keyword(s):  
Rice Varieties ◽  
Tropical Regions ◽  
Short Day ◽  
Days To Heading ◽  
Major Qtl

scholarly journals Combining QTL-seq and linkage mapping to fine map a candidate gene in qCTS6 for cold tolerance at the seedling stage in rice

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Luomiao Yang ◽  
Jingguo Wang ◽  
Zhenghong Han ◽  
Lei Lei ◽  
Hua Long Liu ◽  
...  
Keyword(s):  
Cold Stress ◽  
Cold Tolerance ◽  
Regulatory Gene ◽  
Snp Markers ◽  
Seedling Stage ◽  
Pcr Analysis ◽  
Sequencing Data ◽  
Coding Region ◽  
Rice Varieties ◽  
Major Qtl

Abstract Background Cold stress caused by low temperatures is an important factor restricting rice production. Identification of cold-tolerance genes that can stably express in cold environments is crucial for molecular rice breeding. Results In this study, we employed high-throughput quantitative trait locus sequencing (QTL-seq) analyses in a 460-individual F2:3 mapping population to identify major QTL genomic regions governing cold tolerance at the seedling stage in rice. A novel major QTL (qCTS6) controlling the survival rate (SR) under low-temperature conditions of 9°C/10 days was mapped on the 2.60-Mb interval on chromosome 6. Twenty-seven single-nucleotide polymorphism (SNP) markers were designed for the qCST6 region based on re-sequencing data, and local QTL mapping was conducted using traditional linkage analysis. Eventually, we mapped qCTS6 to a 96.6-kb region containing 13 annotated genes, of which seven predicted genes contained 13 non-synonymous SNP loci. Quantitative reverse transcription PCR analysis revealed that only Os06g0719500, an OsbZIP54 transcription factor, was strongly induced by cold stress. Haplotype analysis confirmed that +376 bp (T>A) in the OsbZIP54 coding region played a key role in regulating cold tolerance in rice. Conclusion We identified OsbZIP54 as a novel regulatory gene associated with rice cold-responsive traits, with its Dongfu-104 allele showing specific cold-induction expression serving as an important molecular variation for rice improvement. This result is expected to further exploration of the genetic mechanism of rice cold tolerance at the seedling stage and improve cold tolerance in rice varieties by marker-assisted selection.

scholarly journals Breeding Temperate Japonica Rice Varieties Adaptable to Tropical Regions: Progress and Prospects

Agronomy ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2253
Author(s):  
Myrish Pacleb ◽  
O-Young Jeong ◽  
Jeom-Sig Lee ◽  
Thelma Padolina ◽  
Rustum Braceros ◽  
...  
Keyword(s):  
The Philippines ◽  
Tropical Region ◽  
Japonica Rice ◽  
Rice Varieties ◽  
Temperate Japonica ◽  
Tropical Regions ◽  
Tropical Environments ◽  
Increasing Demand ◽  
Northeast Asian ◽  
The Tropics

Temperate japonica rice is mainly cultivated in temperate regions. Many temperate japonica varieties have a superior grain quality that is preferred in Northeast Asian countries such as Japan, Korea, and China. The changes in consumers’ preferences in Southeast Asia and Western countries has contributed to increasing the demand for temperate japonica. Most temperate japonica varieties developed in temperate regions typically exhibit extra-early flowering under the short-day conditions in the tropics, which usually results in severely reduced yields. Since 1992, we have been developing temperate japonica varieties that can adapt to tropical environments to meet the increasing demand for temperate japonica rice, having released six varieties in the Philippines. Especially, the yield of one of the temperate japonica varieties, Japonica 7, was comparable to the yields of leading indica varieties in the Philippines. Here, we discuss the current breeding initiatives and future plans for the development of tropical-region-bred temperate japonica rice.

ASSESSING THE COMBINING ABILITY OF RICE GENOTYPES IN F1 GENERATION USING COMPLETE DIALLEL CROSS

2021 ◽  
Vol 36 (2) ◽  
pp. 135-140
Author(s):  
I. A. Odhano ◽  
H. B. Bozdar ◽  
M. A. Sial
Keyword(s):  
Grain Yield ◽  
Short Stature ◽  
Combining Ability ◽  
Panicle Length ◽  
Negative Effects ◽  
Cross Combination ◽  
Rice Varieties ◽  
Early Maturity ◽  
Positive Effects ◽  
Days To Heading

A complete diallel analysis was carried out to determine combining ability of Shandar, NIA-Mehran, NIA-19/A, KS-282 and Shua-92 rice varieties in F1 during 2017. The objective of the study was to identify potential recombinants for future rice breeding program. The research was conducted at Nuclear Institute of Agriculture, Tandojam. Genotypic mean squares were significant (P ?0.01) for all of the traits i.e.; days to heading, days to maturity, plant height, number of tillers plant-1, panicle length, grains panicle-1 and grain yield plant-1 indicating genetic variation. Importance of both additive and non-additive gene action was found with preponderance of additive genetic effects in expression of traits studied. Showing negative GCA effects, NIA-Mehran, NIA-19/A and Shua-92 proved better parent varieties for developing early maturity. While, NIA-Mehran, KS-282 and Shua-92 for developing short stature genotypes. While, Shandar remained the best combiner for yield and yield associated traits with higher positive GCA effects. Cross combination of Shandar × KS-282 was the best with higher negative effects for days to heading and maturity and higher positive effects for grain yield plant-1. NIA-Mehran × Shua-92 gave the highest negative SCA effects indicating best combination for short stature. In case of number of tillers plant-1 and grains panicle-1, the cross NIA-19/A × KS-282 was the better combination with the highest positive SCA effects. Shandar × NIA-Mehran manifested the highest value for panicle length. Findings of reciprocal SCA  revealed that the reciprocal cross combination of Shua-92 × Shandar was fruitful illustrating negative effects for days to heading and maturity. While, KS-282 × NIA-Mehran was the best reciprocal combination for yield and yield associated traits. It is concluded that rice varieties Shandar and NIA-Mehran could be used to improve yield contributing traits in rice, while, NIA-Mehran and KS-282 may be used to improve early maturity and short stature in rice crop.

INFLUENCE OF PHOTOPERIOD, SHORT-DAY VERNALIZATION, AND COLD VERNALIZATION ON DAYS TO HEADING IN AVENA SPECIES AND CULTIVARS

1972 ◽  
Vol 52 (4) ◽  
pp. 471-482 ◽  
Author(s):  
D. R. SAMPSON ◽  
V. D. BURROWS
Keyword(s):  
Wild Species ◽  
Dark Period ◽  
Heading Date ◽  
Vernalization Response ◽  
Breeding Lines ◽  
Short Day ◽  
Avena Strigosa ◽  
Days To Heading ◽  
Oat Cultivars ◽  
Oat Breeding

Exposure of 19 accessions belonging to nine species of Avena to constant daily photoperiods of 9, 12, 15, 18, and 24 hr showed that heading was promoted by the longer photoperiods, except in A. abyssinica, which headed first on 15-hr days. Some accessions headed sooner in 9-hr than in 12-hr photoperiods. An interrupted night treatment suggested that photoperiodic control of heading date is exercised by the length of the dark period. A second experiment demonstrated a short-day vernalization response in two of the six accessions initially grown in 9-hr days and later in 12-hr days. In a third experiment (19 entries) cold vernalization (7.2 C for 39 days) strongly promoted heading in seven wild species from the Mediterranean region and in A. abyssinica and the winter oat Landhafer (from 21 to 60 days earlier in 18-hr days). Weaker but significant (P <.05) responses were evident in A. strigosa and three of the remaining nine cultivated hexaploids. The responses to cold vernalization were greater in plants growing in 12- and 18-hr days than in 9-hr days. For the three experiments, regression analysis of days to heading on hours of photoperiod showed that A. byzantina C.W. 544, A. sativa Rapida, A. abyssinica, A. vaviloviana, and A. barbata were the least sensitive to differences in photoperiod (1–3 days earlier per hour longer). Avena strigosa and related diploid wild species showed intermediate sensitivity. Northern spring oat cultivars and Ottawa breeding lines were very sensitive (6–10 days earlier per hour longer). The implications that these findings have for oat breeding are discussed.

scholarly journals Responses of earliness and lateness genes for heading to different photoperiods, and specific response of a gene or a pair of genes to short day length in rice

Hereditas ◽  
2019 ◽  
Vol 156 (1) ◽  
Author(s):  
Birendra Bahadur Rana ◽  
Misa Kamimukai ◽  
Mukunda Bhattarai ◽  
Yohei Koide ◽  
Masayuki Murai
Keyword(s):  
Genetic Factors ◽  
Day Length ◽  
Specific Response ◽  
Near Isogenic Lines ◽  
Heading Time ◽  
Short Day ◽  
Long Day ◽  
Days To Heading ◽  
Important Trait ◽  
Spring Sowing

Abstract Background Heading time is an important trait for regional and seasonal adaptabilities in rice, and is controlled by genetic factors in relation with environmental factors, mainly day length and temperature. The following genes controlling heading were examined for their responses to six different environmental conditions involving different day lengths using five early near-isogenic lines (NILs) of T65-R and three late NILs of T65wx: two earliness genes, Ef1 and Efx controlling basic vegetative phase (BVG), and m-Ef1, the enhancer to the former gene; and two lateness genes, Se1-pat(t) and se-pat controlling photo-sensitivity and BVG, respectively. T65-R and T65-T were different accessions of Taichung 65. T65wx is a NIL of T65-T carrying wx. Results The five early NILs of T65-R were in the order of ER50 (Ef1, Efx, m-Ef1) < ER40 (Ef1, m-Ef1) ≤ ER20 (Ef1, Efx) < ER1 (Ef1) ≤ ER21 (Efx) < T65-R regarding days to heading (DTH) under two spring-sowing and one summer-sowing paddy field (PF) conditions. The three late NILs of T65wx were in the order of LF3 (Se1-pat(t)) ≤ LF2 (Se1-pat(t), se-pat) ≤ T65wx < LF1 (se-pat) under two short-day conditions (10-h photoperiod condition with artificial-light and natural short-day condition from autumn to winter). The NILs and T65wx were in the order of T65wx < LF3 < LF1 < LF2 under the two spring-sowing PF (long day) conditions. T65-R (Ac-ef1) was 2.8 or 5.1 days earlier in DTH than T65-T (ac-ef1) under the two spring-sowing PF conditions. However, T65-R was 19 and 10 days earlier than T65-T under the two short-day conditions. Conclusions Earliness gene(s) and their combinations reduced DTH regardless of photoperiod lengths. Se1-pat(t) increased DTH under long-day conditions but decreased it under short-day conditions, while se-pat elongated DTH under both short-day and long-day conditions indicating that se-pat is responsible for BVG. The se-pat increased DTH by adding its effect over that of Se1-pat(t) under long-day conditions. However, this increasing effect of DTH by se-pat was almost completely masked when it coexisted with Se1-pat(t) under the short-day conditions. Notably, the response of Ac-ef1 to day length was found to delay heading under the short-day conditions.

Response of rice varieties to short-day treatment

Euphytica ◽  
1954 ◽  
Vol 3 (3) ◽  
pp. 221-228 ◽  
Author(s):  
R. L. M. Ghose ◽  
S. V. S. Shastry
Keyword(s):  
Day Treatment ◽  
Rice Varieties ◽  
Short Day

scholarly journals Desarrollo de variedades tropicales de soya para el consumo humano.

2006 ◽  
Vol 11 (2) ◽  
pp. 1
Author(s):  
Enrique Villalobos ◽  
Fausto Camacho
Keyword(s):  
Soybean Seed ◽  
Yield Potential ◽  
High Yield ◽  
Breeding Programs ◽  
Tropical Regions ◽  
Short Day ◽  
Taste And Odor ◽  
Glycine Max L ◽  
Delayed Flowering ◽  
The University

Soybean (Glycine max L. Merr.) lines lacking seed lipoxigenases 2 and 3 and with high yield potential were developed at the Grain and Seed Research Center of the University of Costa Rica. Those lines were obtained by crossing selected F3 plants from ‘Kanto-101’ X ‘IAC-8’ with F2 plants selected from ‘Padre’ X ‘Duocrop’. Kanto-101 is a Japanese variety that was used as a donor of lox2 and lox3 genes that inhibit the synthesis of lipoxigenases 2 and 3 in the soybean seed. Elimination of lipoxigenases 2 and 3 considerably improves the taste and odor of the soybean milk. Cultivar Padre was used as a donor of delayed flowering under short day conditions. F11 lines CIGRAS-34, 47, 51 and 57 (lox2,lox3), derived from the double cross, showed an outstanding agronomic performance when compared with high yielding cultivars CIGRAS-06 and 10 (Lox), in three sites. The use of Padre cultivar, carrier of the genes that delay flowering under short day conditions, in tropical soybean breeding programs, is important to develop late maturing lines with good adaptation in tropical regions. Lipoxigenase-free seed of soybeans reach a higher price in the international market and might be a potential export crop to those countries where soybeans are an important component of the human diet.

scholarly journals Identification of Candidate Genes Conferring Cold Tolerance to Rice (Oryza sativa L.) at the Bud-Bursting Stage Using Bulk Segregant Analysis Sequencing and Linkage Mapping

2021 ◽  
Vol 12 ◽  
Author(s):  
Luomiao Yang ◽  
Lei Lei ◽  
Peng Li ◽  
Jingguo Wang ◽  
Chao Wang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Cold Tolerance ◽  
Oryza Sativa L ◽  
Chromosome 9 ◽  
Pcr Analysis ◽  
Potential Candidate ◽  
Sequencing Data ◽  
Coding Region ◽  
Rice Varieties ◽  
Major Qtl

Low-temperature tolerance during the bud-bursting stage is an important characteristic of direct-seeded rice. The identification of cold-tolerance quantitative trait loci (QTL) in species that can stably tolerate cold environments is crucial for the molecular breeding of rice with such traits. In our study, high-throughput QTL-sequencing analyses were performed in a 460-individual F2:3 mapping population to identify the major QTL genomic regions governing cold tolerance at the bud-bursting (CTBB) stage in rice. A novel major QTL, qCTBB9, which controls seed survival rate (SR) under low-temperature conditions of 5°C/9 days, was mapped on the 5.40-Mb interval on chromosome 9. Twenty-six non-synonymous single-nucleotide polymorphism (nSNP) markers were designed for the qCTBB9 region based on re-sequencing data and local QTL mapping conducted using traditional linkage analysis. We mapped qCTBB9 to a 483.87-kb region containing 58 annotated genes, among which six predicted genes contained nine nSNP loci. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analysis revealed that only Os09g0444200 was strongly induced by cold stress. Haplotype analysis further confirmed that the SNP 1,654,225 bp in the Os09g0444200 coding region plays a key role in regulating the cold tolerance of rice. These results suggest that Os09g0444200 is a potential candidate for qCTBB9. Our results are of great significance to explore the genetic mechanism of rice CTBB and to improve the cold tolerance of rice varieties by marker-assisted selection.

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