Comparison of selection indices for screening maize (Zea maysL.) germplasm for cold tolerance

Soil salinity is one of the main factors limiting cereal productivity in worldwide agriculture. Exploitation of natural variation in local barley germplasm is an effective approach to overcome yield losses. Three gene pools of North African Hordeum vulgare L. grown in Tunisia, Algeria and Egypt were evaluated at the reproductive stage under control and saline conditions. Assessment of stress tolerance was monitored using morphological, yield-related traits and phenological parameters of reproductive organs showing significant genetic variation. High heritability and positive relationships were found suggesting that some traits associated with salt tolerance could be used as selection criteria. The phenotypic correlations revealed that vegetative traits including shoot biomass, tiller number and leaf number along with yield-related traits such as spike number, one spike dry weight, grain number/plant and grain number/spike were highly positively correlated with grain yield under saline conditions. Hence, these traits can be used as reliable selection criteria to improve barley grain yield. Keeping a higher shoot biomass and longer heading and maturity periods as well as privileged filling ability might contribute to higher grain production in barley and thus could be potential target traits in barley crop breeding toward improvement of salinity tolerance. Multiple selection indices revealed that salt tolerance trait index provided a better discrimination of barley landraces allowing selection of highly salt-tolerant and highly productive genotypes under severe salinity level. Effective evaluation of salt tolerance requires an integration of selection indices to successfully identify and characterize salt tolerant lines required for valuable exploitation in the management of salt-affected areas.

Download Full-text

Cold tolerance is similar but heat tolerance is higher in the alien insect Trichocera maculipennis than in the native Parochlus steinenii in Antarctica

Polar Biology ◽

10.1007/s00300-021-02865-w ◽

2021 ◽

Author(s):

L. R. Pertierra ◽

P. Escribano-Álvarez ◽

M. Á. Olalla-Tárraga

Keyword(s):

Cold Tolerance ◽

Heat Tolerance ◽

Alien Insect

Download Full-text

MaMAPK3-MaICE1-MaPOD P7 pathway, a positive regulator of cold tolerance in banana

BMC Plant Biology ◽

10.1186/s12870-021-02868-z ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Jie Gao ◽

Tongxin Dou ◽

Weidi He ◽

Ou Sheng ◽

Fangcheng Bi ◽

...

Keyword(s):

Transgenic Plants ◽

Cold Tolerance ◽

Molecular Breeding ◽

Cold Resistance ◽

Oxidoreductase Activity ◽

Tropical Fruit ◽

Over Expression ◽

Cavendish Banana ◽

Cold Tolerant ◽

Necrotic Symptoms

Abstract Background Banana is a tropical fruit with a high economic impact worldwide. Cold stress greatly affects the development and production of banana. Results In the present study, we investigated the functions of MaMAPK3 and MaICE1 involved in cold tolerance of banana. The effect of RNAi of MaMAPK3 on Dajiao (Musa spp. ‘Dajiao’; ABB Group) cold tolerance was evaluated. The leaves of the MaMAPK3 RNAi transgenic plants showed wilting and severe necrotic symptoms, while the wide-type (WT) plants remained normal after cold exposure. RNAi of MaMAPK3 significantly changed the expressions of the cold-responsive genes, and the oxidoreductase activity was significantly changed in WT plants, while no changes in transgenic plants were observed. MaICE1 interacted with MaMAPK3, and the expression level of MaICE1 was significantly decreased in MaMAPK3 RNAi transgenic plants. Over-expression of MaICE1 in Cavendish banana (Musa spp. AAA group) indicated that the cold resistance of transgenic plants was superior to that of the WT plants. The POD P7 gene was significantly up-regulated in MaICE1-overexpressing transgenic plants compared with WT plants, and the POD P7 was proved to interact with MaICE1. Conclusions Taken together, our work provided new and solid evidence that MaMAPK3-MaICE1-MaPOD P7 pathway positively improved the cold tolerance in monocotyledon banana, shedding light on molecular breeding for the cold-tolerant banana or other agricultural species.

Download Full-text

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

BMC Plant Biology ◽

10.1186/s12870-021-03076-5 ◽

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.

Download Full-text