Strdy On Genetic Diversity And Germplasm Improvement Of Erianthus Arundinaceus And Erianthus Rockii

Modern sugarcane cultivars are derived from a limited number of inter-specific hybridization events between Saccharum officinarum L. and Saccharum spontaneum L.. The genetic base hence is narrow and difficult to have breakthrough in sugarcane breeding.Intergeneric hybridization between Erianthus arundinacens (Retz.) Jesw. and sugarcane (S. officinarum) is a way for broadening the genetic basis so as to increase the ability of stress resistant. Erianthus rockii Keng, which is originated from China, is another new source of species used for the intergenetic hybridization. A number of attemps in crossing have been performed by using E. arundinaceus or E. rockii with sugarcane, and several hybrids have been identified as genuine. However, lack of the knowledge from the genetic diversity analysis for these two germplasm resources, influences the utilization of targeting to the clones, as well as the more number of clones used in crossing.This study repored the results of the genetic diversity assessment for E. arundinaceus and E. rockii by four analysis levels including:geographic distribution, phenotypic variations, chromosome types and AFLP molecular makers. The study was to learn the genetic base of these species, and to provide the basic information of the relationships between and within existing germplasm collections, for the purpose of conservation of genetic diversity and for targeted sampling of clones for future sugarcane introgression breeding programs.This study meanwhile reports the intergeneric crosses between Saccharum and E. arundinaceus or E. rockii. A series of intergeneric progenies were verified by molecular makers and GISH analysis. The aim was to verify the introgression of E. arundinaceus and E. rockii germplasm into sugarcane, for identifying and evaluating the value of Erianthus germplasm utilization in sugarcane breeding. The innovated germplasm hybrids of BC2, BC3from E. arundinaceus and BC1from E. rockii were selected and being used as new parents in sugarcane variety improvement. The main results from the study were as following:1The genetic diversity of E. arundinaceus and germplasm innovation(1) The geographic distribution were diverse and the phenotypic variations were obvious in elevationsThe information from the data records of the collecting origins was analyzed to assess the geographic distribution for the E. arundinaceus collections in the whole country. The result showed that:the314clones were from14provinces and145counties. The horizontal distribution was in the east longitude of97°36’～121°38and the northern latitude of18°14’～32°28’; the vertical distribution was in the elevation of-24-2627m. The majoy distribution of E. arundinaceus was the south of the Yangze river region, which crossed the tropical and subtropical to the temperate zones. This revealed the ecological adaptability of E. arundinaceus to the diverse geography. Yunnan, Sichuan, Fujian and Hainan were the concentrated regions of the collections.The9phenotypic variations from the108clones preserved in the National Field-Genebank for Sugarcane Germplasm were analyzed. The results showed that:the average variation coefficient from5quantitative characters was28.62%from a range of16.22～40.01%, in which the highest was from the Lamina width (41.01%) and the lowest was from the Lamina length (16.22%). The others were the Stalk length (22.08%), the Brix (20.42%) and the Stalk diameter (17.27%). This meant that the main phenotypic variation of E. arundinaceus was from the Lamina width.In the different elevation regions, the phenotypic variation coefficients were obvious:the Brix was21.56%in the middle latitude area and9.97%in the low area; the Stalk length was23.24%in the middle and12.8%in the high latitude areas. The variation coefficient of Lamina width was higher in the high latitude area than in the middle and low latitude area; the variation coefficient of Stalk length was higher in the middle and low latitude areas than in the high latitude area. The Shannon-Wiener coefficient from4qualitative characters showed that the Hair group57was the highest (0.9917).(2) Three types of chromosome number of E. arundinaceus were observed:2n=60、40、30The cytological observation of pollen mother cells showed:there were three types of chromosome number observed:2n=60、40、30. The type of60and40were observed in Yunnan materials, and the60and30were observed in Guizhou and Fujian materials. Most materials were the main type of60and had wide geographic distribution with more phenotypic variations. Several materials were observed as40and30, the former was originated in the western of Yunnan province and the latter was from Guizhou and Fujian. The type of60presented the varied types of the agronomic characters, the type of40presented higher stalk length, and the type of30presented as shorter stalk length.(3) The diversity of AFLPs was high and differences existed among areasFurther analyses from the DNA level was conducted based on the above studies. The207materials of E. arundinaceus accessions mainly from China, and part of other countries including:Indonesia, India, New Guinea, Philippines and Vietnam, were sampled for genetic diversity analysis using AFLP markers. The results showed that:(i) the highest diversity level was found within the Chinese collection and lowest within the Indonesian collection;(ii) the genetic similarity showed that the materials from Philippines were found more similar to the Chinese collection, while the ones from India were opposite.(iii) There was a general division amongst clones from China based on those collected from eastern versus western parts of the country, and clones from Yunnan province (western China) were the most diverse.(4) Crosses combination between sugarcane and E. arundinaceus spp. were successful conducted to produce seedlings identified to be genuine hybrids, and2innovated germplasm clones were selected. Hybrid utilization of E. arundinaceus germplasm was performed by manual crossing with S. officinarum clones or sugarcane cultivars, which were inducted flowering by photoperiodic induction.19crosses combination between sugarcane and F1, BC1or BC2of E. arundinaceus were successful conducted to produce1332seedlings,11of them were identified to be genuine hybrids. The2innovated germplasm clones (BC207-106、BC307-131) were selected and applied the Plant Protection Rights.2The genetic diversity of E. rockii and germplasm innovation(1) The geographic distribution were diverse and the western part of Yunnan province was the main diverse area, the phenotypic variations were obvious in elevationsThe information from the data records of the collecting origins was analyzed to assess the geographic distribution for60E. rockii collections. The result showed that: the horizontal distribution was in the east longitude of95°53’～103°25and the northern latitude of22°30’～28°40’;40of55Yunnan clones were originated in the western of Yunnan. The vertical distribution was in the elevation of-693～2340m. The ecosystem was rich in this area so as to form the diverse geographic distribution.The phenotypic variation was mainly from the quantitative traits of Stalk length and Brix, and the qualitative trait of Internode colour exposed. The variation coefficient of Stalk length was higher in the middle latitude area than in the high latitude area; the variation coefficient of Brix was higher in the middle latitude areas than in the high latitude area. The Shannon-Wiener of the qualitative characters showed that the Internode colour exposed was the highest (1.3113).(2) Only one type of chromosome number of E. rockii was observed:2n=30The cytological observation of pollen mother cells showed:only one type of chromosome number was observed:2n=30. Total4materials were identified as this type and their geographic locations were far distance. Also, the elevations were obviously different as well as the phenotypic characters.(3) The diversity of AFLPs was high level in E. rockii collectionFurther analyses from the DNA level was conducted based on the above studies. The39materials of E. rockii accessions mainly from Yunnan, and2from Sichuan and Guizhou, were sampled for genetic diversity analysis using AFLP markers. The results showed that:(i) the highest diversity level was found within the Dehong collection in Yunnan, and the second was the Baoshan collections;(ii) the genetic similarity showed that the clones from Dehong was found more similar to the Baoshan;(iii) the genetic relationship was basically match to the geographic area, the ones from Baoshan and Dehong were clustered to be a major group.(4) The chromosome transmission from the parents of S. officinarum and E. rockii to F1was found as" n+n"GISH methods was conducted to analyze the chromosome composition in F1(03-316) arising from the cross between Vietnam Niuzhe (S. officinarum) and Yunnan92-20(E. rockii). The aim was to characterize the genome structure of hybrids derived from E. rockii, for providing information that could be used in designing effective introgression breeding strategies. The results showed that:(i) the chromosome numbers of Yunnan92-20(E. rockii) was identified as2n=30; the chromosome numbers of F1was observed as54, in which39from the male and15from the female;(ii) the chromosome transmission was n+n by the male parentand the female parent into F1generation. This first reported by GISH that the chromosome transmission from the intergeneric hybridization of S. officinarum and E. rockii was n+n, which was not as the2n+n of "Nobilization"as the interspecific hybrids among the species in Saccharum genera(5) Crosses combination between S. officinarum and E. rockii were successful conducted to produce seedlings identified to be genuine F1hybrids, and a innovated germ plasm clone was selected.Hybrid utilization of E. rockii germplasm was performed by manual crossing with S. officinarum clones or sugarcane cultivars, which were inducted flowering by photoperiodic induction.12crosses combination between sugarcane and E. rockii clone&F1were successful conducted to produce857seedlings,62of F1and3BC1were identified to be genuine hybrids. E. rockii BC106-279was selected to be an elite innovation germplasm to obtain the acception of PBR.