The contribution of distant hybridization with decaploid Agropyron elongatum to wheat improvement in China

Wheat is a staple food crop in the world as well as in China. Because of the progress of wheat breeding and other agricultural ＂sci-technologies, the wheat grain yield per unit area has increased more than five folds from 1952 to 2006 in China. The first part of this article briefly reviews the history of wheat breeding in China. Second, the establishment of ＂Triticum aestivum-Agropyron＂ distant hybridization system and its contribution to wheat production and breeding in China are summarized. Finally, the future challenges of wheat breeding are discussed, which include how to increase the utilization efficiencies of water, soil nutrient and light energy through breeding. As an example, our research progress on how to increase light use efficiency in wheat through breeding is introduced and discussed.

Innovation on Distant Hybridization of Saline-tolerant Mud Flat Spartina and Rice Germplasm

To explore saline-tolerant high yield Spartina and rice germplasm resources,innovate upon distant hybridization technology,and develop new saline-tolerant mud flat Spartina germplasm,autonomous patent for invention was used to study distant hybridization of Spartina and rice in 2005- 2016. The study adopted tidal flat planting screening,phenotypic screening,molecular marker assisted selection,to find biological evidences of new germplasm,and also applied crossbreeding,conventional breeding,and molecular breeding,to select new saline-tolerant Spartina and rice varieties. With 12 years of efforts,the team developed 1498 crossbreeding combinations and established pedigree file and seed bank,tested 307 crossbreeding materials(57 hybrid seeds showed parental genetic components of Spartina and Rice); obtained Spartina/ Rice distant hybridization and seed setting,transplanting,hybridization material economic traits,and molecular biological experimental evidences; Rice♀× Spartina ♂ hybridization success rate of 1. 04- 1. 39%; obtained authorization of patent for invention of Distant Hybridization Methods for Spartina and Rice; formulated procedures for high yield cultivation of Spartina-Rice,planted 33. 33 hm2Spartina-Rice in coastal saline and alkaline land,cultivated 10 new saline-tolerant Spartina-Rice varieties,and the rice yield up to 5. 925- 8. 28 t / hm2. Results indicate that Spartina-Rice is saline-tolerant high yield rice germplasm,developed through sexual hybridization,conventional breeding,and molecular breeding technologies,and is optimal crop for saline and alkaline land. Success of Spartina-Rice solves the problem of saline-tolerant crop badly for transformation of saline and alkaline land,the problem of feeds for herbivores,as well as problem of environmental pollution resulted from straw burning. Besides,it is of essential scientific significance for resource utilization,increase of agricultural efficiency,grain security,and farmland strategy,so it has broad application prospect.

Creating New Germplasm by Distant Hybridization in Stone Fruits:Ⅰ.Effects of Different Treatments on Cross Compatibility of Distant Hybridization inStone Fruits

The effects of different treatments on cross compatibility in distant hybridization werestudied in 69 cross combinations among 9 cultivars of stone fruits. The results showedthat the setting percentage in balloon stage was obviously higher than that in earlyblooming stage. The differences of fruit set between positive and reverse crosses weresignificant. Female parent affected cross compatibility more remarkably than male parentin distant hybridization. The appropriate electrostatic field, He-Ne laser combinedtreatment with 60Co γ-ray and He-Ne laser could improve the pollen germination rate invitro effectively, the fruit set percentage was higher than control, while 60Co γ-raytreatment reduced the pollen germination rate in vitro, and the fruit set percentageobtained by distant hybridization was lower than control.

Improvement of Fiber Quality by Distant Hybridization in the Green Cotton

In order to improve fiber quality of green cotton,a wide hybrid was used between a green fiber cotton and Sea Island cotton.The results show that the hybrid F1 plants were stable,but F2

Creating New Germplasm by Distant Hybridization in Stone Fruits:Ⅱ-Embryo Rescue and Hybrid Identification Between Plum and Apricot

Embryo abortion stage and rescue system of hybrids were studied in the distant hybridizationbetween plum and apricot. Identification of the hybrids was also made. The resultsshowed: (1) Embryo abortion started from three weeks after pollination. (2) The germinationand growth of embryos were different at different growth stages, which could germinateand grow with PF value>0.5, but failed with PF value<0.5. In embryo rescue system ofhybrids, the best germination and differentiation medium was MS+6-BA 2mgL-1+IAA 0.3mgL-1,the rate of germination and differentiation reached up to 80%, bud induction andmultiplication medium was MS+6-BA 1.5mgL-1+IAA 0.3mgL-1, rooting medium was 1/2 MS+IAA0.8mgL-1. Some hybrids were transplanted into the field successfully. (3) Leaf shapeinvestigation and identification by S allele-specific PCR and RAPDs showed that thehybrids were true ones.

Research on the Distant Hybrids of Wheat Obtained via Low-Energy Ion-Beam Implantation

The whole DNA of soybean was implanted into four varieties of wheat of Zhongyu 5, Huaiyin 9628, Wenyou 1, Jimai 5 respectively via ion-beam mediation. There were 5 plants obtained whose protein content was higher than 18.5 %, the highest one was 21.44 %. There were 3 plants obtained whose protein content was lower than 11.5%, the lowest one was 10.96%. We can see that the whole DNA of soybean transformed into wheat via ion beam implantation can induce the increase in wheat protein content dramatically. The result also shows that the transformation efficiency of different gene types of wheat receptor varies greatly that the implanting time has a certain effect on the efficiency of transformation.

Inter-specific and Inter-generic Hybridization Compatibility of Eriobotrya Species (Loquat) and Related Genera

We studied the cross-compatibility among 91 inter-specific combinations and 21 inter-generic combinations in 7 Eriobotrya plants and 2 related genera(Raphiolepis indica Lindl. and Photinia serrulata Lindl.) using emasculation, bagging, and artificial pollination. Our results showed that28 of the 91 inter-specific combinations set no fruit, which means nearly 30% of the combinations were incompatible. In the remaining 63 combinations, most showed partial cross-compatibility, and a few showed complete cross compatibility. Eriobotrya plants were incompatible with plants from their related genera(R. indica Lindl. and P. serrulata Lindl.). Backcrossing produced 5 compatible combinations, which could set fruits and produce F1 progeny but only after embryo rescue. Fruit setting ratios varied among various species used as male or female parents.E. prinoides Rehd. & Wils., common loquat(E. japonica) and Eriobotrya × daduheensis, used as female parents resulted in an average fruitsetting ratio of 36.2%–58.2%. E. deflexa Nakai and its two forms, and E. elliptica Lindl. as female parents resulted in 2.9%–16.3% average fruitsetting ratio; however, the fruit set ratio was higher(22.4%–43.1%) if they were used as male parents. Failure of E. deflexa f. koshunensis Nakai × E.prinoides Rehd. & Wils. hybrids to set fruit could be attributed to sporophytic incompatibility.

An improved hybrid bream derived from a hybrid lineage of Megalobrama amblycephala(♀)×Culter alburnus(♂)

Distant hybridization is an important technique in fish genetic breeding.In this study,based on the establishment of an allodiploid fish lineage(BT,2n=48,F_(1)–F_(6))derived from distant hybridization between female Megalobrama amblycephala(BSB,2n=48)and male Culter alburnus(TC,2n=48),and the backcross progeny(BTB,2n=48)derived by backcrossing female F_(1) of BT to male BSB,an improved hybrid bream(BTBB,2n=48)was obtained by backcrossing BTB(♀)to BSB(♂).Moreover,the morphological and genetic characteristics of BTBB individuals were investigated;BTBB was similar to BSB in appearance but had a higher body height than BSB.The study results regarding chromosome numbers and DNA content indicated that BTBB is a diploid hybrid fish.The 5S rDNA and Hox gene of BTBB were inherited from the original parents.Gonadal development in BTBB was normal.On the other hand,BTBB had a faster growth rate,higher muscle protein level,and lower muscle carbohydrate level than BSB.Hence,bisexual fertile BTBB is promoted and can be applied as a high-quality fish,and it can also be used as a new fish germplasm resource to develop high-quality fish further.Thus,this study is of great significance for fish genetic breeding.