Low temperature seed germination of cucumber: genetic basis of the tolerance trait

ABSTRACT Cucumber (Cucumis sativus L.) germinates in an optimal temperature ranging from 24 to 28 °C. In order to develop cultivars with low temperature germination ability, knowledge regarding its genetic basis is needed. In our earlier study, we identified the accession PI 390953 as chilling tolerant and a good cold germinator. The objective of our present study was to compare cold germinability of cold tolerant breeding line B 5669 with PI 390953, and to measure the inheritance of this trait. At 13 °C, both tested cultigens (B 5669, PI 390953) showed the highest germinability and we found no significant differences between them regarding the rate of germination, days to germination (DTG), or germination index (GI). We also observed differences in the germination ability at 13 °C among seven hybrid populations of cucumber, derived from the cross between good cold germinator B 5669 (P1) and B 6115 (P2) lacking cold-germination ability. The fastest low temperature germination and the highest low temperature germination percentages were observed in B 5669 (P1) with germination of 78 and 100% on the 6th and 10th day of the test, respectively. In addition, the cultigen B 5669 exhibited the fastest germination, reaching on average of DTG = 5.7. B 6115 (P2) and BC1P2 proved unable to germinate at 13 °C even within 21 days. The seed germinability of F2 population fits a three-recessive gene model. Cucumber cultigens B 5669, PI 390953, and PI 246903 showed low temperature tolerance, but of them B 5669 may become the most desirable to breeders since it exhibits cold germinability combined with good fruit quality traits.

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QTL Mapping Low-Temperature Germination Ability in the Maize IBM Syn10 DH Population

Plants ◽

10.3390/plants11020214 ◽

2022 ◽

Vol 11 (2) ◽

pp. 214

Author(s):

Qinghui Han ◽

Qingxiang Zhu ◽

Yao Shen ◽

Michael Lee ◽

Thomas Lübberstedt ◽

...

Keyword(s):

Transcription Factor ◽

Low Temperature ◽

Candidate Genes ◽

Temperature Tolerance ◽

Bhlh Transcription Factor ◽

Rna Seq ◽

Dh Population ◽

Low Temperature Tolerance ◽

Germination Ability ◽

Upregulated Genes

Chilling injury poses a serious threat to seed emergence of spring-sowing maize in China, which has become one of the main climatic limiting factors affecting maize production in China. It is of great significance to mine the key genes controlling low-temperature tolerance during seed germination and study their functions for breeding new maize varieties with strong low-temperature tolerance during germination. In this study, 176 lines of the intermated B73 × Mo17 (IBM) Syn10 doubled haploid (DH) population, which comprised 6618 bin markers, were used for QTL analysis of low-temperature germination ability. The results showed significant differences in germination related traits under optimum-temperature condition (25 °C) and low-temperature condition (10 °C) between two parental lines. In total, 13 QTLs were detected on all chromosomes, except for chromosome 5, 7, 10. Among them, seven QTLs formed five QTL clusters on chromosomes 1, 2, 3, 4, and 9 under the low-temperature condition, which suggested that there may be some genes regulating multiple germination traits at the same time. A total of 39 candidate genes were extracted from five QTL clusters based on the maize GDB under the low-temperature condition. To further screen candidate genes controlling low-temperature germination, RNA-Seq, in which RNA was extracted from the germination seeds of B73 and Mo17 at 10 °C, was conducted, and three B73 upregulated genes and five Mo17 upregulated genes were found by combined analysis of RNA-Seq and QTL located genes. Additionally, the variations of Zm00001d027976 (GLABRA2), Zm00001d007311 (bHLH transcription factor), and Zm00001d053703 (bZIP transcription factor) were found by comparison of amino sequence between B73 and Mo17. This study will provide a theoretical basis for marker-assisted breeding and lay a foundation for further revealing molecular mechanism of low-temperature germination tolerance in maize.

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Tetraploidy enhances the cold-resistance in yellow kiwifruit (Actinidia chinensis)

10.21203/rs.2.21136/v1 ◽

2020 ◽

Author(s):

Yipei Li ◽

Xiaozhen Liu ◽

Zhou Wei ◽

Zhimin Zhang ◽

Wen Bian ◽

...

Keyword(s):

Survival Rate ◽

Low Temperature ◽

Cold Tolerance ◽

Regulatory Networks ◽

Temperature Tolerance ◽

Temperature Treatment ◽

Actinidia Chinensis ◽

Low Temperature Tolerance ◽

Low Temperature Treatment ◽

Cold Tolerant

Abstract Yellow kiwifruit ( Actinidia chinensis ) is highly susceptible to severe weather, such as low temperature and frost, which may affect the production in the coming year. And the cold-resistant mechanism of kiwifruit associated with gene regulation is poorly investigated. To botain cold-resistant germplam, to provide insight into the causes of differences in low temperature tolerance due to ploidy and to better understand cold-adaptive mechanisms in tetraploid kiwifruit, the diploid yellow kiwifruit ‘SWFU03’ and its tetraploid plantlets were subjected to cold-tolerant screening with L-hydroxyproline (L-Hyp) and low temperature, the selected ones were then analyzed by transcriptome data and confirmed by RT-qPCR. The results showed that the survival rate of tetraploid plants was 62.22% when treated with 8 mmol/L L-Hyp for 30 days, while all the diploid ones died. After treated with 0°C for 12 h, then at room temperature for seven days, the survival rate of tetraploid plantlets was 42.22%, while all diploidy died. Hence, cold tolerance of the tetraploid plantlets was stronger than that of the diploid genotypes. Using these two screening systems, 126 cold-resistant tetraploid tissue culture plantlets were obtained. A total of 1630 differentially expressed genes (DEGs) were identified, of which 619 were up-regulated and 1011 were down-regulated in the low temperature treatment goup. The DEGs enriched in the cold-tolerance related pathways mainly included plant hormone signal transduction, and starch and sucrose metabolism pathway. RT-qPCR analysis confirmed the expression levels of eight up-regulated genes in these pathways in the cold-resistant mutants. In conclusion, this study has identified cold-resistant yellow kiwifruit plantlets and cold-tolerance related genes. Moreover, the dataset got in this study advances our knowledge of the cold-adaptive genes in the regulatory networks and leads to understand the cold tolerance mechanisms in the tetraploid yellow kiwifruit.

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Screening Ornamental Pepper Cultivars for Temperature Tolerance Using Pollen and Physiological Parameters

HortScience ◽

10.21273/hortsci.46.6.878 ◽

2011 ◽

Vol 46 (6) ◽

pp. 878-884 ◽

Cited By ~ 17

Author(s):

Bandara Gajanayake ◽

Brian W. Trader ◽

K. Raja Reddy ◽

Richard L. Harkess

Keyword(s):

Low Temperature ◽

Pollen Viability ◽

Temperature Tolerance ◽

Physiological Parameters ◽

Tube Length ◽

Limited Information ◽

Low Temperature Tolerance ◽

Cold Tolerant ◽

Cold Sensitive ◽

Cardinal Temperatures

Temperature affects reproductive potential, aesthetic, and commercial value of ornamental peppers (Capsicum annuum L.). Limited information is available on cultivar tolerance to temperature stress. An experiment was conducted using pollen and physiological parameters to assess high and low temperature tolerance in ornamental peppers. In vitro pollen germination (PG) and pollen tube length (PTL) of 12 morphologically diverse ornamental pepper cultivars were measured at a range of temperatures, 10 to 45 °C with 5 °C increments. Cell membrane thermostability (CMT), chlorophyll stability index (CSI), canopy temperature depression (CTD), and pollen viability (PV) were measured during flowering. From the modified bilinear temperature–PG and PTL response functions, cardinal temperatures (Tmin, Topt, and Tmax) for PG and PTL and maximum PG (PGmax) and PTL (PTLmax) were estimated. Cultivars varied significantly for PG, PTL, cardinal temperatures for PG and PTL, and all three physiological parameters. Cumulative temperature response index (CTRI) of each cultivar, calculated as the sum of 12 individual temperature responses derived from PV, PGmax, PTLmax, Tmin, Topt, and Tmax for PG and PTL, CMT, CTD, and CSI were used to distinguish differences among the cultivars and classify for high (heat) and low (cold) temperature tolerance. Based on CTRI–heat, cultivars were classified as heat-sensitive (‘Black Pearl’, ‘Red Missile’, and ‘Salsa Yellow’), intermediate (‘Calico’, ‘Purple Flash’, ‘Sangria’, and ‘Variegata’), and heat-tolerant (‘Chilly Chili’, ‘Medusa’, ‘Thai Hot’, ‘Explosive Ember’, and ‘Treasures Red’). Similarly, cultivars were classified for cold tolerance as cold-sensitive, moderately cold-sensitive, moderately cold-tolerant, and cold-tolerant based on CTRI–cold. ‘Red Missile’ and ‘Salsa Yellow’ were classified as cold-tolerant. Cultivar screening using pollen parameters will be ideal for reproductive temperature tolerance, whereas physiological parameters will be suitable for screening vegetative temperature tolerance. The identified heat- and cold-tolerant cultivars are potential candidates in breeding programs to develop new ornamental and vegetable pepper genotypes for high and low temperature tolerance.

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Lowest Survival Temperature (LST) Estimations in 33 Varieties of Viburnum by Controlled Freezing

HortScience ◽

10.21273/hortsci.31.4.579e ◽

1996 ◽

Vol 31 (4) ◽

pp. 579e-579

Author(s):

John F. Wachter ◽

Paul E. Cappiello

Keyword(s):

Low Temperature ◽

Temperature Tolerance ◽

Visual Observation ◽

Stem Cuttings ◽

Low Temperature Tolerance ◽

Cold Tolerant ◽

Controlled Freezing

Stems of 33 varieties of Viburnum were screened for low temperature tolerance on five dates. Terminal stem cuttings were shipped overnight to Orono, Maine, from Oregon, Michigan, and Minnesota. Following a controlled freezing regime, stems were incubated for 7–14 days and evaluated for injury by visual observation. Lowest survival temperatures (LST) were estimated as the lowest temperature at which 100% of stems were uninjured. Varieties of V. dentatum, V. lantana, V. opulus, and V. trilobum were rated as consistently very cold tolerant. Viburnum ×pragense, V. dilatatum, and V. rufidulum were rated as consistently moderately cold tolerant. All V. tomentosum varieties showed inconsistent LST estimates. Varieties from the Oregon source were rated as cold intolerant. Direct comparisons by variety and source will be discussed with emphasis on consistent LST estimates. Rates of deacclimation as they occurred over the five testing dates will also be discussed.

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Lowest Survival Temperature (LST) Estimations in Kalmia, Viburnum, and Magnolia by Controlled Freezing

HortScience ◽

10.21273/hortsci.32.3.508d ◽

1997 ◽

Vol 32 (3) ◽

pp. 508D-508

Author(s):

John F. Wachter ◽

Paul E. Cappiello

Keyword(s):

Low Temperature ◽

Test Temperature ◽

Temperature Tolerance ◽

Stem Cuttings ◽

Kalmia Latifolia ◽

Low Temperature Tolerance ◽

Cold Tolerant ◽

Controlled Freezing

Stems of 38 varieties of Kalmia latifolia, 33 varieties of Viburnum, and 45 varieties of Magnolia were screened for low-temperature tolerance on eight dates during the winters of 1995–96 and 1996–97. Terminal 6- to 8-cm stem cuttings were shipped overnight on ice to Orono, Maine, and processed immediately upon arrival. Cuttings were subjected to a controlled freezing regime with a lowest test temperature ranging from –31°C to –42°C. Following freezing, stems were incubated for 5 to 14 days at 21°C and evaluated for injury. Lowest survival temperatures (LST) for each variety were estimated as the lowest temperature at which 100% of stems were undamaged. Varieties of Viburnum dentatum, V. lantana, V. opulus, and V. trilobum were rated as consistently very cold-tolerant, with LSTs of at least –36°C on all test dates. All V. plicatum var. tomentosum varieties showed inconsistent survival and LST estimations. Midwinter LST estimates in Kalmia latifolia showed 40% of the tested varieties remained undamaged at or below –36°C. Ten percent of K. latifolia varieties tested were damaged at –24°C or warmer, with the remaining varieties having LSTs somewhere between –24°C and –40°C. Varieties of Magnolia showed inconsistent survival with LSTs estimated for only 5% of those tested. Direct comparisons by variety, test date and source will be discussed with emphasis on consistent LST estimation. Varieties of K. latifolia, Viburnum, and Magnolia best suited for use in northern landscapes will also be discussed.

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