| The Lotus corniculatus is not only a high-protein forage grass and an ornamental lawn plant,but also an ecological grass and has very broad application prospects.Therefore,it has become an significant approach to improve its utilization value by choosing and breeding Lotus varieties of high yield and high quality.Using Leo(Lotus corniculatus L.cv.’Leo’),Mirabal(Lotus corniculatus L.cv.’Mirabal’)and Georgia(Lotus corniculatus L.cv.’Georgia’)as controls,the yield,nutrient quality and photosynthetic indexes of introduced 61 Russia Lotus corniculatus germplasm materials were measured in this study in Hexi corridor of China.Comprehensive evaluation of yield traits,nutrient quality and photosynthetic characteristics were carried out by grey correlation degree analysis and clustering analysis,finally correlation analysis and path analysis were used to explore the correlation between the production performance and photosynthetic physiological parameters.This study aimed to provide theoretical basis for future large-scale promotion,planting and utilization of high quality of Lotus japonicus germplasm resources by screening germplasm resources with different traits and production needs.Results showed as follows:1.The heigh of germplasm materials ranged from 36 to 84 cm,the fresh yield was varied between 6516.04 and 55374.60 kg·hm-2,the dry yield was continuing from the beginning of 1628.75 to 10407.61 kg·hm-2.The regeneration speed and regeneration intensity were0.38-2.19 cm·d-1 and 0.60-5.72 g·m-2·d-1,respectively.According to four main traits(dry yield,heigh,regeneration speed and regeneration intensity),the introduced 61 Russia Lotus corniculatus materials were divided into three clusters by clustering analysis.The first cluster consisted of a total of 12 matrials and Mirabal with good production property,such as Zxy06p-2338(X11),Zxy06p-2376(X12),Zxy08p-4693(X23)and so on.The second cluster comprised of 38 materials and Leo,Georgia,which belong to medium production property,including Zxy06p-1648(X2),Zxy06p-2228(X9),Zxy08p-4779(X26)etc.,The third cluster had a total of 11 materials,which could be regarded as poor production property,including Zxy06p-2116(X6),Zxy06p-2287(X10),Zxy08p-5019(X30),and so on.The results through using simple correlation analysis showed that the extremely significant positive correlation were existed in the dry yield and plant heigh,in regeneration speed and regeneration intensity,which correlation coefficient was 0.69 and0.71.2.The phosphorus has the most obvious variation(12.96%).The variation coefficients of calcium,relative feed value and crude protein were quite obvious(11.66%、10.47%、 9.13%).The variation coefficients of acid detergent fiber,neutral detergent fiber and ether extract were 8.65%、8.07%、6.33%,which was also obvious.The variation of dry matter was inconspicuous(0.35%).According to the grey relational degree weighted analysis,the weighted grey correlative degree of Zxy09p-5647(X41),which had the highest nutritive value.The higher nutritive value of germplasm materials,included Zxy08p-4687(X22),Zxy08p-5070(X32),Zxy09p-5809(X44),Zxy09p-6485(X60)and Georgia.The intermediate nutritive value consisted of 38 germplasm materials and Mirabal,Leo,which showed total materials of only62.30%,including Zxy06p-1775(X4),Zxy09p-5991(X45),Zxy06p-2663(X14),Zxy09p-6275(X48),Zxy08p-4892(X27).The low nutritive value contained 21 germplasm materials,which was about 29.51% of the total,such as Zxy06p-1608(X1),Zxy08p-4768(X25),Zxy08p-5019(X30),Zxy09p-5694(X43),Zxy09p-6268(X47).3.The photosynthetic characteristics of these materials were comprehensively evaluated by the grey relational degree weighted analysis and clustering analysis.Based on the weight of photosynthesis index,the results showed that these materials were clustering into three groups.Group 1 was composed of 12 germplasm materials with good photosynthesis characteristics,including Zxy06p-1648(X2),Zxy08p-4693(X23),Zxy09p-5642(X40),ect.Zxy08p-4693(X23),Zxy06p-2376(X12),Zxy09p-5642(X40),Zxy09p-6464(X57),Zxy09p-6300(X49)ranked from the first to the fifth.Group 2 was comprised of 28 germplasm materials with medium photosynthesis characteristics,such as Zxy06p-2205(X8),Zxy08p-4916(X28),Zxy09p-6365(X52),and the Mirabal,Georgia.Group 3 contained 21 germplasm materials with poor photosynthesis characteristics,including Zxy06p-2287(X10),Zxy08p-4528(X16),Zxy09p-5809(X44)and Leo.4.The introduced 61 Russia Lotus corniculatus materials planted in northwest oasis area were analyzed by correlation analysis and path analysis.The results indicated that there was a extremely significant positive correlation between photosynthetic rate,stomatal conductance and intercellular CO2 concentration(P<0.01),and the correlation coefficient was 0.89 and 0.67.The transportation rate showed extremely significant negative correlation with water use efficiency(P<0.01).There was a extremely significant positive correlation between stomatal conductance and intercellular CO2 concentration(P<0.01).The significantly negative correlations was found between stomatal limitation value and photosynthetic rate,transportation rate,intercellular CO2 concentration,stomatal conductance(P<0.01).The results through path analysis showed that the direct affects of other photosynthetic parameters on the photosynthetic rate of Lotus corniculatus materials were stomatal conductance(P= 1.06)> stomatal limit value(P = 1.00)> intercellular CO2 concentration(P =0.56)> water use efficiency(P=0.51)> Transpiration rate(P=0.43).In summary,the greatest influence on the photosynthetic rate of Lotus corniculatus materials is the stomatal conductance,followed by the stomatal limit value.5.The production performance and photosynthetic parameters of the introduced 61 Russia Lotus corniculatus materials were analyzed by correlation analysis and path analysis.The results indicated that there the significantly positive correlations was found between photosynthetic rate of leaves and dry yield(P<0.01),direct path analysis parameter was maximum(P=0.93),and the correlation coefficient was highest(r=0.71).There was a highly significant positive correlation between plant height and photosynthetic rate(P<0.01),and the correlation coefficient was 0.61.The transpiration rate,intercellular CO2 concentration,stomatal conductance,water use efficiency,and stomatal limit values had relatively little or no direct or indirect effects on dry yield of Lotus corniculatus materials.The correlation between quality characteristics and photosynthetic parameters of Lotus corniculatus materials did not reach significant levels(P>0.05).On the summed-up results,photosynthetic rate was the major determinant trait of dry yield and plant height of Lotus corniculatus.6.The yield traits,quality characteristics and photosynthetic performance of 61 Russia Lotus corniculatus germplasm materials were comprehensively evaluated by the grey relational degree weighted analysis and clustering analysis.The results showed that the first cluster contained a toatal of 14 materials and Mirabal,Georgia with better comprehensive traits,including Zxy06p-1648(X2),Zxy06p-1785(X5),Zxy08p-4693(X23),Zxy08p-4892(X27),Zxy09p-5809(X44),Zxy09p-6368(X53),and so on.The second cluster had a toatal of 38 materials and Leo,which could be regarded as intermediate comprehensive traits,such as Zxy06p-1775(X4),Zxy06p-2205(X8),Zxy08p-4687(X22),Zxy08p-5365(X34),Zxy09p-5647(X41),Zxy09p-6471(X58)etc.The third cluster comprised of 9 materials including Zxy08p-4589(X19),Zxy08p-4779(X26),Zxy08p-5019(X30),Zxy09p-5991(X45),Zxy09p-6019(X46),Zxy09p-6339(X50),Zxy09p-6358(X51),Zxy09p-6401(X54),Zxy09p-6478(X59),which belonged to poor comprehensive traits. |
