China's pioneer in cotton marker breeding was initiated by Lu 05H9

Recently, the new red-flower-marked insect-resistant hybrid cotton variety Lu 05H9, bred by the Cotton Center of the Shandong Academy of Agricultural Sciences, passed the approval of the National Crop Variety Approval Committee. The red flower marker is like putting an anti-counterfeiting label on transgenic insect-resistant hybrid cotton. This variety pioneered red-flower trait marker breeding in cotton in China, and it is also the first of its kind worldwide.

According to researcher Wang Liuming, the breeder of the variety, Lu 05H9 red-flower-marked insect-resistant cotton was developed over 12 years through distant hybridization, transferring the HB red-flower trait of wild G. bickii cotton onto cultivated insect-resistant hybrid cotton. This new variety bears pink flowers with large purplish-red basal spots at the base of the petals. At full bloom, the cotton field is a sheet of pink, with no other off-color flowers. In contrast, other cotton varieties currently grown in China all bear creamy-white or pale yellow flowers, which turn red only after pollination, and have no basal spots or inconspicuous basal spots. Therefore, whether viewed plant by plant or across the cotton field, a mixed appearance of red and white flowers occurs. The visible trait of the red flower marker makes transgenic hybrid cotton bearing this marker very easy to distinguish from ordinary cotton, handing the right to identify true and false hybrid cotton to farmers, which is more conducive to regulating market order and protecting farmers' interests.

Like most crops, cotton also shows obvious heterosis. However, as the cotton market has developed to this day, the problems of too many hybrid cotton varieties, disorder, and mixture have become increasingly prominent, and the purity and quality of hybrid cotton seed are difficult to control effectively. Because cotton plants have an indeterminate growth habit, different varieties are relatively difficult to distinguish in a population state. Fraudulent practices such as substituting and passing off hybrid cotton on the market and mixing F2 generation seed into the F1 generation of hybrid cotton occur from time to time. This not only directly harms the interests of the vast number of cotton farmers, but also prevents the varietal characteristics of hybrid cotton from being fully expressed in large-scale production, thereby lowering its due production level and affecting the healthy development of the hybrid cotton industry. Lu 05H9 uses the red flower as a marker trait, and the high-heterosis intervarietal hybrid bred from a female parent and a male parent both carrying the Bt insecticidal gene provides a convenient and rapid technical approach for detecting and controlling the seed purity of the hybrid F1 generation, becoming an important breakthrough in hybrid cotton breeding in the Yellow River Basin cotton region.

It is understood that in the national regional trial of new cotton varieties, Lu 05H9 showed an obvious yield-increasing advantage over similar varieties. In the two-year regional trial in the hybrid cotton region of the Yellow River Basin, the average seed cotton and lint cotton yields per mu were 247.8 kg and 102.0 kg respectively, 9.5% and 9.6% higher than the control Lumianyan No. 15, ranking first among the varieties tested in the same group. Production demonstrations in various places all show that this variety emerges well, has strong seedling vigor, is tolerant to Fusarium wilt and Verticillium wilt, is highly resistant to cotton bollworm, has good high and stable yield, and has relatively good fiber quality, with good value for promotion and application.