Screening of Bitter Gourd Hybrid Combinations with High Yield and Disease Resistance

Baibi ZHU, Yu NIU, Yan YANG, Huang HE, Ziji LIU

Abstract [Objectives] This study was conducted to breed and promote high-yield and disease-resistant varieties of bitter gourd.

[Methods] The comparison experiments of six new hybrid combinations （Z1705， Z1706， Z1717， Z1721， Z1732， Z1745） were successively carried out at two experimental sites of Danzhou and Tunchang.

[Results] Comparing the agronomic traits and disease resistance of various combinations， it was concluded that Z1717 and Z1721 have high yields， green and glossy fruit surface and good comprehensive disease resistance， so they can be popularized and planted.

[Conclusions] This study is of great significance for improving the yield of bitter gourd and increasing economic benefits.

Key words Bitter gourd; Fusarium wilt; Powdery mildew; Hybrid combination

Received： May 20， 2022  Accepted： July 25， 2022

Supported by Hainan Science and Technology Project （No.ZDYF2020229）; Scientific Research Program of Hainan Key Laboratory of Vegetable Biology and Hainan Key Laboratory for Quality Regulation of Tropical Horticultural Crops （No.HNZDSYS（YY）-03）.

Baibi ZHU （1982-）， female， P. R. China， assistant research fellow， master， devoted to research about genetics and breeding of cucurbits.

*Corresponding author. E-mail： liuziji1982@163.com.

The bitter gourd （Momordica charantia L.， 2n=2x=22） is an annual trailing herbaceous plant belonging to the Momordica genus of Cucurbitaceae[1-2]. As one of the main vegetable crops grown in winter in Hainan Province， bitter gourd is not only rich in nutritional value， but also contain pharmacologically active ingredients that have anti-tumor[3]， hypoglycemic[4-5] and anti-inflammatory effects[6-7]. The bitter gourd has wide adaptability and a long harvest period. With the publics full understanding of the nutritional value and medicinal value of bitter gourd， the production of bitter gourd in China has developed rapidly， and the cultivation area has expanded year by year， which has promoted the in-depth development of bitter gourd breeding research. Breeding and popularizing disease-resistant varieties is of great significance for increasing the yield of bitter gourd and increasing economic benefits.

Materials and Methods

Materials

The materials were Z1705， Z1706， Z1717， Z1721， Z1732 and Z1745， a total of six new hybrid combinations of bitter gourd， and the control varieties were Changlv No.2 （Danzhou） and Fenglv （Tunchang）. The plot area was 30 m2， and a randomized block design was adopted， with three repetitions. The planting density was 1.5-2.0 m between rows and 80 cm between plants.

Trait investigation

During the full bearing period， the fruit longitudinal diameter， fruit transverse diameter， flesh thickness， single fruit weight， fruit color， fruit shape， powdery mildew resistance， and fusarium wilt resistance of different combinations of bitter gourd were investigated. The yield of different bitter gourd combinations was counted.

Experimental data analysis

The calculation of means and multiple comparisons were performed using SAS9.0 software.

Results and Analysis

Comparative analysis on main agronomic traits of different bitter gourd hybrid combinations （Danzhou）

A total of six bitter gourd hybrid combinations （Z1705， Z1706， Z1717， Z1721， Z1732， Z1745） were tested for product comparison. The control variety was Changlv No.2， and the experimental site was Danzhou Experimental Base. There were significant differences in agronomic traits among different bitter gourd hybrid combinations （Table 1）. Z1717 has the largest longitudinal diameter of 30.23 cm， which was 15.8% larger than the control variety， and Z1705 had the smallest longitudinal diameter of 22.23 cm， which was 14.8% smaller than the control. Z1721 had the largest fruit transverse diameter of 7.23 cm， and the fruit transverse diameters of other five hybrid combinations were slightly smaller than that of the control variety. The flesh thicknesses of the six bitter gourd hybrid combinations were basically the same as that of the control variety. The single fruit weight of Z1717 was the largest of 553.03 g， which was 22.7% larger than that of the control variety. The single fruit weight of Z1721 was the second， which was 532.50 g， and the single fruit weight of Z1705 was the smallest of 357.23 g. The fruit color of Z1705 and Z1732 was the same as that of the control variety， which was light green， and the fruit color of other four hybrid combinations was green. Z1705， Z1706， Z1732 and Changlv No.2 were short rod-shaped， and other three combinations were long rod-shaped. Except for Z1705， other combinations had strong growth vigor.

Comparative analysis on yields of different bitter gourd hybrid combinations （Danzhou）

The yield of Z1717 was the highest， followed by Z1721， and the values were 21 700.05 and 20 365.05 kg/hm2， respectively， which were significantly higher than that of the control variety， 25.9 and 18.2% higher than that of the control variety Changlv No.2， respectively. The yields of Z1706 and Z1745 were higher than that of the control variety， but there were no significant difference from the control variety. The yield of Z1705 was the lowest of 10 960.05 kg/hm2， which was 36.4% lower than that of the control variety （Table 2）.

Comparative analysis on resistance of different bitter gourd combinations （Danzhou）

A total of six bitter gourd hybrid combinations and the control variety were analyzed for their resistance levels to powdery mildew and fusarium wilt. The hybrid combinations Z1705， Z1706 and Z1721 were susceptible to powdery mildew with disease indexes of 55， 60 and 55， respectively， while Z1717， Z1732， Z1745 and the control variety Changlv No.2 showed moderate disease resistance with disease indexes of 43， 38， 32 and 42， respectively. Z1705 and Z1706 were highly susceptible to fusarium wilt of bitter gourd with disease indexes of 82 and 75， respectively. Z1732， Z1745 and the control variety Changlv No.2 were susceptible to fusarium wilt of bitter gourd with disease indexes of 59， 68 and 56， respectively. Z1717 and Z1721 showed moderate resistance to fusarium wilt of bitter gourd with disease indexes of 39 and 42， respectively （Table 3）.

Yield analysis of different bitter gourd hybrid combinations （Tunchang）

The hybrid combination Z1721 had the highest yield of 24 394.95 kg/hm2， followed by Z1706， and Z1717 ranked the third. There were no significant differences in the yield among Z1721， Z1706 and Z1717， but the values were significantly higher than the control variety Fenglv， specifically， 48.7%， 48.0% and 44.7% higher than the control variety， respectively. The yield of Z1705 was the lowest of 14 250.00 kg/hm2， which was significantly lower than that of the control variety， specifically， 13.1% lower than that of the control variety. The first female flower nodes of Z1706， Z1717 and Z1745 were lower than that of the control variety， and the maturity was earlier than that of the control variety （Table 4）. A total of six hybrid combinations of bitter gourd and the control variety were analyzed for their resistance levels to powdery mildew and fusarium wilt. The hybrid combination Z1705 was susceptible to powdery mildew with a disease index of 58， while Z1706 and Z1745 were moderately resistant to the disease with disease indexes of 41 and 38， respectively. Z1717， Z1721， Z1732 and Fenglv （control variety） showed resistance to powdery mildew with disease indexes of 19， 25， 28 and 26， respectively. Z1705， Z1706， Z1732 and Z1745 were highly susceptible to fusarium wilt of bitter gourd with disease indexes of 95， 86， 80 and 75 respectively.

The control variety Fenglv was susceptible to fusarium wilt of bitter gourd with a disease index of 55. Z1717 and Z1721 exhibited moderate resistance to fusarium wilt of bitter gourd with disease indexes of 45 and 39， respectively （Table 5）.

Conclusions

The bitter gourd hybrid combinations Z1717 and Z1721 have high yields， green and glossy fruit surface and good comprehensive disease resistance， deserving commercial extension.

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