Screening and Evaluation of Saline–Alkaline Tolerant Germplasm of Rice (Oryza sativa L.) in Soda Saline–Alkali Soil

Hao Wang,Shenkui Liu,Tetsuo Takano

doi:10.3390/agronomy8100205

Abstract

The improvement and development of saline–alkali land is of great significance for promoting food production and sustainable development. It is necessary to study the mechanism of saline–alkaline tolerance and breed saline–alkaline tolerant crops to improve the utilization of saline–alkali land. For this study, we conducted a three-year pot experiment to screen the saline–alkaline tolerant germplasm of 72 rice genotypes from hundreds of elite cultivars during the whole growth period using a certain proportion of soda saline–alkali soil. The selected salt-tolerant variety was combined with a salt-sensitive variety to analyze the saline–alkaline tolerance mechanism by using the saline–alkaline soil leachate. We eliminated 36 genotypes with low seedling survival rates under salt–alkali stress, and the salt-tolerant Jiudao-66 (D68) variety had a higher survival rate than most varieties. The membership degree of Jiudao-66, according to the salt tolerance index of multiple agronomic traits, is higher than that of 34 varieties, with a higher survival rate except when compared to D36. The survival rate and these salt tolerance indexes of Jiudao-66 were significantly higher than those of Kitaake (salt-sensitive). Under the stress of leachate, the content of proline and soluble sugars in the shoots of Jiudao-66 were higher than that of Kitaake, and the total antioxidant capacity was stronger than that of Kitaake. However, the content of malondialdehyde was lower than that of Kitaake. Additionally, the Na+/K+ ratios in shoots and roots were not significantly differently between Kitaake and Jiudao-66. The results showed that Jiudao-66, as a salt-tolerant variety, is more tolerant to salt and alkali in a near-natural state due to its stronger tolerance of osmotic stress, and it can accumulate more proline and soluble sugars under stress. At the same time, Jiudao-66 also has a stronger antioxidant capacity. Its ion regulation ability has no obvious advantage.

Highlights

Arable land supports grain production and is a fundamental guarantee of national food security.Soil saline–alkalization is a major abiotic stressor on the world’s agriculture, causing considerable damage to crop growth and resulting in serious losses in crop production [1,2,3,4]
We investigated the effect of saline–alkaline soil on the survival rate of rice seedlings at 30 days after transplanting
The survival rates of seedlings under saline–alkaline stress decreased to 45.6–97.8%

Summary

Introduction

Arable land supports grain production and is a fundamental guarantee of national food security. Soil saline–alkalization is a major abiotic stressor on the world’s agriculture, causing considerable damage to crop growth and resulting in serious losses in crop production [1,2,3,4]. The salinization area of land has exceeded 800 million hectares worldwide [5]. The saline–alkali land area of China is about 100 million hectares, mainly distributed in northeast, northwest, and north China, as well as coastal areas [6]. The area of saline–alkali land in the Songnen Plain in northeast China has reached. 3.73 million hectares [7]. Saline–alkaline soil can be mainly classified into two types: saline soil and Agronomy 2018, 8, 205; doi:10.3390/agronomy8100205 www.mdpi.com/journal/agronomy

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Discussion

Conclusion