Characteristic Evaluation Of Intergeneric Hybrids Of BC₃F₁ Iines Of Saccharum Officinarum×erianthus Arundinaceus

Sugarcane cultivars in China were mainly the hybrid progenies of Saccharum.spontaneum and Saccharum.officinarum L,which have narrow genetic basis and are difficult to break through in breeding.Erianthus arundinaceus was a wild species of Saccharum related genus（Erianthus Michaux.sect.Ripidium Henrard）,which has strong drought resistance,good disease resistance,strong root system,good ratooning and other excellent characteristics.Using the distant hybridization between Erianthus arundinaceus and Saccharum,introducing the excellent resistance genes of Erianthus arundinaceus can broaden the genetic basis,obtain breakthrough germplasm or parents,and accelerate the improvement of sugarcane varieties.In this study,14 BC₃F₁lines of intergeneric hybrids between Saccharum officinarum and Erianthus arundinaceus,which were bred and identified in our laboratory,were evaluated for one-year new planting and one-year ratooning in the field.The germplasm or parents with strong resistance and excellent characters were screened out,which provided excellent breeding materials for sugarcane variety improvement.The main findings were as follows:（1）The chlorophyll content,Gs,Pn and Tr in leaves of 14 new BC₃F₁ lines and the control（Liucheng 05-136）showed a rising trend at the seedling stage,tillering stage and jointing stage,while Ci was decreased with the development of growth stage.Among them,the above-mentioned parameters of five lines,including HE15-30,HE15-71,HE15-77,HE15-61 and HE15-63 were higher than CK in the three growth periods.（2）The activities of SOD,POD,CAT,and content of soluble sugar and soluble protein in the leaves of 14 BC₃F₁ lines and the control at seedling stage,tillering stage,jointing stage and elongation stage all showed an upward trend,among them,the above-mentioned parameters of HE15-30,HE15-71,HE15-77,HE15-61 and HE15-63 were higher than those of CK at four growth stages.The MDA content of leaves showed a downward trend,among which,the MDA content of HE15-30,HE15-71,HE15-77,HE15-61 and HE15-63 were lower than CK in four growth periods.（3）In the experiment of new planting and ratoon,from the early stage of sugarcane elongation to the early stage of maturity,the expression levels of neutral/alkaline invertase gene（So NIN1）and sucrose synthetase gene（So Su S1）in the leaves in HE15-30,HE15-71,HE15-77,HE15-61 and HE15-63 were significantly higher than that in the control,while the expression level of acid invertase gene（So SAI1）in the five lines was significantly lower than that in the control.（4）According to the comprehensive evaluation of lodging resistance of new plants and ratoons,six lines（CK,HE15-19,HE15-81,HE15-40,HE15-77 and HE15-30）with strong lodging resistance accounted for 40%;eight lines with moderate lodging resistance accounted for 53.33%;only one line（HE15-87）with weak lodging resistance accounted for6.67%in new planting.There were six lines with strong lodging resistance（CK,HE15-31,HE15-19,HE15-61,HE15-77 and HE15-63）,accounting for 40%;eight lines with moderate lodging resistance（53.33%）;only one line with weak lodging resistance（HE15-84）,accounting for 6.67%in the ratoon.（5）In the experiment of new planting and ratooning,the single stem weight and sucrose content of 14 BC₃F₁ lines were significantly lower than CK;except HE15-30,HE15-61,HE15-63,HE15-71 and HE15-77,the cane yield of the other nine BC₃F₁ lines in the new planting were significantly lower than CK;except HE15-81,the cane yield of the other 13BC₃F₁ lines in the ratoon were significantly lower than CK.（6）Based on the mathematical model of principal component analysis and cluster analysis,12 indexes of 14 BC₃F₁ lines and control,including economic characters,lodging resistance,photosynthetic and physiological characteristics,were evaluated.New plants:Two lines（HE15-71 and HE15-77）with excellent variety traits,accounting for 13.33%;four lines（HE15-63、HE15-30、HE15-61 and CK）with good variety traits,accounting for26.67%;four lines（HE15-14、HE15-19、HE15-31、HE15-81）with medium variety traits,accounting for 26.67%;five lines（HE15-55,HE15-40,HE15-84,HE15-87 and HE15-49）with poor variety traits,accounting for 33.33%.Ratoon:One line（HE15-71）with excellent variety traits,accounting for 6.67%;four lines（HE15-30,HE15-61,HE15-63 and HE15-77）with good variety traits,accounting for 26.67%;one line（CK）with medium variety traits,accounting for 6.67%;nine lines（HE15-19,HE15-31,HE15-55,HE15-81,HE15-14,HE15-87,HE15-84,HE15-40 and HE15-49）with poor variety traits,accounting for 60%.（7）HE15-30,HE15-71,HE15-77,HE15-61 and HE15-63 had better according to agronomic,economic and stress resistance.