Analysis of inherited tendency of fruit characteristics in F1 group of reciprocal crossing between ‘Yanshanzaofeng’ and ‘Yanjing’ in Castanea mollissima

  Objective  This paper aims to improve the breeding efficiency of chestnut varieties by studying the genetic tendency and genetic differences of chestnut hybrid offspring.

  Method  Using ‘Yanshanzaofeng’ and ‘Yanjing’ as the parental crosses, 259 F1 individuals were produced as test materials. 13 traits of chestnut were measured in 2016 and 2017, including nut-related traits, bur-related traits, amylose content, amylopectin content, total starch content, and soluble sugar content, and the genetic tendency research was conducted.

  Result  Research on nut-related traits showed that the traits such as single nut mass, nut thickness, nut height and nut width showed a normal distribution trend, and the average value of offsprings was greater than the mid-parent value, indicating an additive effect in 2016 and 2017. The coefficient of variation of the single-nut mass traits of the offsprings of reciprocal crosses for two consecutive years was 18.5%−20.19%. The offsprings were widely separated and had high genetic diversity. It is possible to breed chestnut varieties with larger single-nut mass. The coefficient of variation of nut width, thickness and height traits were all less than 20%, and genetic transmitting ability was between 98.54%−106.55%, indicating that nut traits were less affected by the environment. The research on the bur-related traits showed that the average value of the bur mass of the progeny of reciprocal crosses was higher than mid-parent value for two consecutive years, the coefficient of variation of the reciprocal crosses was greater than 20%, and the genetic transmitting ability was between 112.0%−117.44%. It can be inherited stably and was less affected by the environment. For two consecutive years, the ultra-high parent rate of the bur width in the offsprings of reciprocal crosses reached 37.50% and 23.96%, and the genetic transmitting ability was 112.50% and 113.93%, respectively. In 2016, the average value of the progeny and the orthogonal progeny in 2017 of the prickle length were less than mid-parent value, and the genetic transmitting ability was 90.25%, 90.83% and 93.66%. The ultra-low parent rate in 2016 was 27.08% and 18.9%, respectively. Prickle length tend to become shorter. Research on fruit quality-related traits showed that the range of the coefficient of variation of starch-related traits in the offsprings of reciprocal crosses for two consecutive years was 7.82%−17.66%, and the genetic transmitting ability of amylopectin content was between 101.11% and 108.22%. The ultra-high affinity rate of the offspring of reciprocal crosses in 2016 was higher than that in 2017, which were 34.38% and 30.09%, respectively, tending to increase the content of amylopectin. Compared with 2017, the genetic transmitting ability of soluble sugar content in the offspring of reciprocal crosses in 2016 was lower, being 64.1% and 59.94%, respectively, indicating genetic instability and greater environmental impact.

  Conclusion  Through the study of the genetic tendency and segregation characteristics of these traits, it is concluded that nut-related traits can be inherited stably, and fruit quality traits are genetically unstable and are greatly affected by the environment. This research provides reference for the screening of the offspring of chestnut cross breeding and the prediction of target traits in the future.