Shiliuyun-Xinjiang Daily (Reporter Xie Huibian) news: On the early morning of April 9, 2025, in the thousands of mu of high-standard farmland in Aktikan Village, Seyek Township, Yopurga County of Kashi Prefecture in northwest China’s Xinjiang, dozens of cotton seeders roared in formation, precisely planted purple cotton seeds into the earth—these purple seeds hold the ultimate code that enables Xinjiang cotton to withstand heat.

Ekrem Mamatming, the cotton farmer, leaned casually against his pickup truck, his fingertips tapping the door in rhythm with the sowing machine. A villager shouted, "What crop are you planting this year?" Ekrem flicked the cuffs of his trousers, spotlessly clean of dirt, and smiled, "Same old recipe!"

The "old recipe" Ekrem referred to is the heat-resistant cotton variety called "Yuanmianxin 13305," which took Li Xueyuan's team from the Institute of Cotton Research of Xinjiang Academy of Agricultural Sciences over a decade to cultivate.

File photo taken on October 5, 2024 shows an on-site observation and exchange meeting for the "Hundreds of Thousands of Mu-Scale High-Yield Demonstration" project aimed at enhancing the per-unit-area yield of cotton crops on a large scale in Xinjiang held in Aksu Prefecture, northwest China’s Xinjiang Uygur Autonomous Region. (Photo by Shiliuyun-Xinjiang Daily/Xie Huibian)

From small-scale trial planting to large-scale cultivation, Ekrem has been growing this variety for four consecutive years. "This variety not only can withstand high temperatures, but it also produces a high yield, maintains stable quality, and is relatively easy to manage," Ekrem chatted with the villagers by the field as if bragging about his own child.

More than a decade ago, the period from late June to early July was Ekrem's most anxious time. "I almost had to check the weather forecast every day. During this period, the temperature was high, and the cotton plants couldn't stand the heat, causing large areas of cotton bolls to fall off," Ekrem said. It was heartbreaking to see the tops of the cotton plants bare, standing there like miniature telephone poles.

Ekrem's experience was once a shared pain in the memories of many cotton farmers in Xinjiang.

Against the backdrop of global warming, extreme high-temperature weather events occur frequently every June to July. This period coincides with the crucial stages of cotton flowering and boll formation. High temperatures lead to significant issues such as massive shedding of cotton buds and bolls, dry buds, deformed bolls, and stunted small bolls, resulting in a reduction of cotton yield by over 15 percent and a decline in quality.

"The core issue is pollen sterility caused by high temperatures," said Wang Junduo, a researcher at the Institute of Cotton Research of the Xinjiang Academy of Agricultural Sciences.

To overcome this technical challenge, in 2012, the Institute of Cotton Research of the Academy collaborated with the team led by Academician Zhang Xianlong from Huazhong Agricultural University, starting with research on the mechanisms of cotton's heat tolerance to cultivate heat-resistant cotton varieties. This endeavor was almost a ground-up effort.

The research team established observation networks in regions such as Alar in southern Xinjiang and Turpan in eastern Xinjiang. At the experimental fields located at the foot of the Flaming Mountains in Turpan City, the team's researchers braved scorching heat waves, conducting field sampling for over 20 consecutive days. "We had to start working in the fields at six o'clock every morning and finish around ten o'clock," Wang Junduo explained while organizing his experimental notes. "As soon as dawn broke, the temperature in the fields at the foot of the Flaming Mountains could approach 35°C, and by ten o'clock in the morning, it could even exceed 40°C." To capture crucial breeding data, Wang Junduo emphasized the urgency of completing sample collection before the natural dehiscence (release of pollen) from the cotton anthers. This was a golden window period for ensuring the effectiveness of the experimental samples. Only by racing against time to capture this critical data could we ensure the effectiveness of our experimental samples, allowing us to precisely screen for superior germplasm resources with strong heat resistance through molecular marker technology.

Through years of relentless effort spanning over a decade, the research team has successfully unraveled the "collapse mechanism" of cotton anthers under high temperatures, identified heat-resistant genes, and cultivated new heat-tolerant cotton varieties. Additionally, leveraging molecular marker technology, they have, for the first time, constructed a genome-wide DNA methylation map of cotton anthers in response to high temperatures.

"It's akin to creating a heatstroke pathology report for cotton," Wang Junduo explained. The research team discovered that cotton anthers during the tetrad stage are most sensitive to high temperatures, with pollen activity plummeting when temperatures exceed 35°C. Countless experiments have demonstrated that high temperatures can trigger epigenetic variations in cotton, leading to abnormal degradation of the tapetal cells, ultimately resulting in loss of pollen viability.

An even more thrilling breakthrough has been achieved in the field of breeding. The research team has developed KASP (Kompetitive Allele-Specific PCR) molecular marker technology, which can precisely pinpoint heat-resistant genes like a "gene radar." In the natural high-temperature laboratories of places like Turpan, 50 heat-tolerant germplasm materials have been identified from tens of thousands of samples. The new cotton varieties, Yuanmianxin 13305 and Xin 19075, bred using these materials as parents, have demonstrated the ability to maintain relatively stable yields even under continuous high-temperature conditions exceeding 35°C for a week.

This research achievement was awarded the First Prize of the 2024 Natural Science Award of Xinjiang Uygur Autonomous Region, marking the first-ever natural science prize in the agricultural field in Xinjiang. The evaluation committee, composed of four academicians and five renowned experts in the industry, recognized that, "this research focuses on the critical needs of China's cotton industry development, fills multiple gaps in the research on cotton heat tolerance, and is highly original, reaching an internationally leading level."

Behind these substantial achievements lies a commitment that transcends time and space. Every summer, the research team divides into three groups, one stationed in Turpan to record extreme high-temperature data, another conducting accelerated breeding in south China's Hainan, and a third analyzing vast amounts of genetic samples in a laboratory in Wuhan City, central China's Hubei Province.

In Wang Junduo's phone album, there's still a contrasting photo: in 2016, after a period of high temperatures, the experimental fields were filled with withered and yellowed cotton plants, while in 2024, the same plot of land showcased lush and vibrant heat-resistant new cotton strains, forming a stark contrast.

Currently, heat-resistant cotton varieties are undergoing production performance evaluations in both northern and southern Xinjiang. In Qiongkuerqiake Township, Bachu County, cotton farmer Abulikem Samat has just finished planting this year's cotton. He shared, "Last July, we had a week of continuous high temperatures, but more than 300 mu (about 20 hectares) of cotton fields of mine still maintained a stable yield of over 500 kilograms per mu, with excellent quality."

At the Alar Cotton Comprehensive Experimental Station of the Xinjiang Academy of Agricultural Sciences, a new generation of drought-resistant and heat-tolerant cotton seeds has just been sown. These seeds, carrying multiple stress-resistant genes, will continue to face multiple extreme environmental challenges this summer.

"We are working on creating functional cotton varieties that are heat-tolerant, resistant to wilt disease, and suitable for mechanical harvesting," said Li Xueyuan, a researcher at the Institute of Cotton Research of the Xinjiang Academy of Agricultural Sciences. "In the future, Xinjiang cotton varieties will not only be heat-resistant but will also boast excellent overall performance and adaptability to a wide range of extreme environmental conditions.

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