Comprehensive evaluation of shade tolerance of alfalfa and screening of identification indexes

doi:10.17521/cjpe.2024.0070

Abstract

Abstract:

Aims Alfalfa (Medicago sativa) is an important forage in the intercropping system. However, the extreme weak light environment in the intercropping system often leads to a significant decrease in alfalfa yield, and breeding shade-tolerant cultivars is the main way to solve this bottleneck problem.

Methods In this study, 20 alfalfa germplasm resources were used as test materials, and the shading rates were 0 (full light), 52.9% (moderate shading) and 71.8% (heavy shading) were used to determine the changes in six morphological indexes (stem diameter, height, number of primary lateral root, number of root nodule, number of root crown tiller, angle of stem to leaf), seven growth indexes (leaf mass, plant biomass, leaf area, specific leaf area, the percentage of leaf mass, stem mass and root mass in total biomass), and five physiological indexes (chlorophyll a content, chlorophyll b content, total chlorophyll content, carotenoid content, chlorophyll a/b ratio) during the tillering stage of alfalfa under different light intensities. Based on the shading rates of 0 and 52.9%, principal component analysis, membership function analysis, cluster analysis, and stepwise regression analysis were used to comprehensively evaluate the shade tolerance of alfalfa germplasm resources and screen their identification indicators.

Important findings (1) The stem diameter, the number of root nodule, and the number of root neck tillering of alfalfa decreased with the decrease of light intensity. The total chlorophyll content showed an increasing trend. The number of primary lateral root, leaf dry mass, biomass per plant, and leaf area showed a trend of first increase and then decrease, while the trends of other indexes were inconsistent, and there were significant differences among different cultivars. (2) Combining principal component analysis, membership function analysis and cluster analysis, the 20 test materials could be divided into three types according to their shade tolerance: shade tolerant (4 test materials), semi-shade tolerant (8 test materials), and shade-sensitive (8 test materials). (3) By stepwise regression analysis, the optimal regression equation was established: D = -0.108 + 0.071X₁₀ + 0.049X₆ + 0.208X₁₄ + 0.027X₄ + 0.096X₇ + 0.052X₃ + 0.048X₅, the precision of estimation was above 93.72%. Seven indexes, including leaf area, leaf dry mass, angle between stem and leaf, number of root nodules, number of primary lateral roots, number of root neck tillering, and chlorophyll a content were selected as shade tolerance identification indexes for alfalfa. The results would provide good materials and scientific basis for the breeding of alfalfa cultivars with shade tolerance, and contribute to the construction and optimization of alfalfa intercropping systems.

Key words: Medicago sativa, shade tolerance, comprehensive evaluation, multivariate statistical analysis, identification index

ZHANG Kun, QIAN Min, WANG Yang, LI Zhi-Hua, KONG Ling-Na, LI Ming-Yang, MA Jin-Yu, YUSUPU Nueraihemaiti, CHEN Yi-Yi, CHENG Yi-Rui, ZHANG Huan-Shi, QIN Feng-Fei, QU Hui. Comprehensive evaluation of shade tolerance of alfalfa and screening of identification indexes[J]. Chin J Plant Ecol, 2025, 49(5): 773-787.

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URL: https://www.plant-ecology.com/EN/10.17521/cjpe.2024.0070

https://www.plant-ecology.com/EN/Y2025/V49/I5/773

Figures/Tables 10

References 33

[1]	An F, Lin WF (2005). Significances of plant shade-tolerance study and its advances. Chinese Journal of Tropical Agriculture, 25(2), 68-72.
	[ 安锋, 林位夫 (2005). 植物耐荫性研究的意义与现状. 热带农业科学, 25(2), 68-72.]
[2]	Animal Husbandry and Veterinary Bureau of Ministry of Agriculture and Rural Affairs of PRC, National Animal Husbandry Station of PRC (2022). Licensed Cultivars of Herbage Crops in China (1987-2020). China Agriculture Press, Beijing.
	[ 农业农村部畜牧兽医局, 全国畜牧总站 (2022). 中国审定登记草品种集(1987-2020). 中国农业出版社, 北京.]
[3]	Cai Z, Wang QC, Zhang Y, Xu LQ, Li QY (2023). Nutrient uptake strategy selection by first-order roots of Juglans mandshurica under shading and phosphorus limitation. Chinese Journal of Applied Ecology, 34, 3239-3244.
	[ 蔡智, 王庆成, 张勇, 徐立清, 李秋雨 (2023). 遮阴和磷限制下胡桃楸1级根养分吸收策略选择. 应用生态学报, 34, 3239-3244.] DOI
[4]	Chen Z, Lin SZ, Cao GQ (2010). The influence of different light treatments on the leaf color and pigment content of Ficus microcarpa cv. golden leaves. Journal of Green Science and Technology, (12), 180-181.
	[ 陈芝, 林思祖, 曹光球 (2010). 不同光照处理对黄心榕叶色及色素含量的影响. 绿色科技, (12), 180-181.]
[5]	Chi W, Wang RF, Zhang CL (2001). Changes of photosynthetic characteristics of strawberry leaf under shading. Chinese Journal of Applied Ecology, 12, 566-568. PMID
	[ 迟伟, 王荣富, 张成林 (2001). 遮荫条件下草莓的光合特性变化. 应用生态学报, 12, 566-568.]
[6]	Ding AP, Wang R, Zhang ZW (2009). Selection of shade-tolerance identification indices for 12 garden plant species. Plant Physiology Communications, 45, 55-59.
	[ 丁爱萍, 王瑞, 张卓文 (2009). 12种园林植物耐荫性鉴定指标的筛选. 植物生理学通讯, 45, 55-59.]
[7]	Gommers CMM, Visser EJW, St Onge KR, Voesenek LACJ, Pierik R (2013). Shade tolerance: When growing tall is not an option. Trends in Plant Science, 18(2), 65-71. DOI PMID
[8]	Hong FZ, Ren JZ (2001). The Development of Grassland Industry in Western China. China Agriculture Press, Beijing.
	[ 洪绂曾, 任继周 (2001). 草业西部大开发. 中国农业出版社, 北京.]
[9]	Hu TH, Cheng LQ, Wang J, Lü JW, Rao QL (2020). Evaluation of shade tolerance of peanut with different genotypes and screening of identification indexes. Scientia Agricultura Sinica, 53, 1140-1153. DOI
	[ 胡廷会, 成良强, 王军, 吕建伟, 饶庆琳 (2020). 不同基因型花生耐荫性评价及其鉴定指标的筛选. 中国农业科学, 53, 1140-1153.] DOI
[10]	Li Y, Zhao HM, You YL, Wu RX, Liu GB (2019). Evaluation on production performance and economic benefit of the single alfalfa filed interplanting different forage crops in summer. Acta Prataculturae Sinica, 28(2), 73-87.
	[ 李源, 赵海明, 游永亮, 武瑞鑫, 刘贵波 (2019). 单作紫花苜蓿田夏季套作不同饲草作物生产性能、效益评价. 草业学报, 28(2), 73-87.] DOI
[11]	Lin CH, McGraw RL, George MF, Garrett HE (1998). Shade effects on forage crops with potential in temperate agroforestry practices. Agroforestry Systems, 44, 109-119.
[12]	Liu GY, Zhou W, Chen L, Wang H, Jin QJ, Wang YJ, Li N, Xu YC (2020). Comprehensive evaluation of shade tolerance of 11 Nymphaea tetragona cultivars. Journal of Plant Resources and Environment, 29(1), 44-51.
	[ 刘光杨, 周炜, 陈磊, 王华, 金奇江, 王彦杰, 李娜, 徐迎春 (2020). 11个睡莲品种的耐阴性综合评价. 植物资源与环境学报, 29(1), 44-51.]
[13]	Nieuwhof M, Garretsen F, 1991). Growth analyses of tomato genotypes grown under low energy conditions. Netherlands Journal of Agricultural Science, 39, 191-196.
[14]	Page W, Morgan PW, Finlayson SA, Childs KL, Mullet JE, Rooney WL (2002). Opportunities to improve adaptability and yield in grasses: Lessons from Sorghum. Crop Science, 42, 1791-1799.
[15]	Pu KG, Ding DX, Li NH, Zhang M, Wang TT, Xie JM, Li J (2024). Effects of Zeaxanthin on photosynthesis capacity and xanthophyll cycle of pepper under low temperature and weak light. Agricultural Research in the Arid Areas, 42(2), 177-187.
	[ 蒲凯国, 丁东霞, 李能慧, 张淼, 王甜甜, 颉建明, 李静 (2024). 玉米黄质对低温弱光下辣椒光合能力和叶黄素循环的影响. 干旱地区农业研究, 42(2), 177-187.]
[16]	Puglielli G, Laanisto L, Poorter H, Niinemets Ü (2021). Global patterns of biomass allocation in woody species with different tolerances of shade and drought: evidence for multiple strategies. New Phytologist, 229, 308-322. DOI PMID
[17]	Qin FF, Li Q, Cui ZM, Li HP, Yang ZR (2012). Leaf anatomical structures and ecological adaptabilities to light of three alfalfa cultivars with different fall dormancies under shading during overwintering. Chinese Journal of Plant Ecology, 36, 333-345.
	[ 覃凤飞, 李强, 崔棹茗, 李洪萍, 杨智然 (2012). 越冬期遮阴条件下3个不同秋眠型紫花苜蓿品种叶片解剖结构与其光生态适应性. 植物生态学报, 36, 333-345.] DOI
[18]	Qin FF, Li ZH, Liu XB, Qu H, Pingcuo ZM, Luosong QC, Su MH (2020). Effects of exogenous 2,4-epibrassinolide on the growth and photosynthesis of alfalfa under high temperature and low light stress in summer. Acta Prataculturae Sinica, 29(9), 146-160.
	[ 覃凤飞, 李志华, 刘信宝, 渠晖, 平措卓玛, 洛松群措, 苏梦涵 (2020). 外源2,4表油菜素内酯对越夏期高温与弱光胁迫下紫花苜蓿生长和光合性能的影响. 草业学报, 29(9), 146-160.] DOI
[19]	Qin FF, Shen YX, Zhou JG, Wang QS, Sun ZC, Wang B (2010). Seedling morphology and growth responses of nine Medicago sativa varieties to shade conditions. Acta Prataculturae Sinica, 19(3), 204-211.
	[ 覃凤飞, 沈益新, 周建国, 王庆师, 孙志成, 王波 (2010). 遮荫条件下9个紫花苜蓿品种苗期形态及生长响应. 草业学报, 19(3), 204-211.]
[20]	Shi J, Zhang H, Yin GL, Chen W, Chen BJ (2014). Effect of shading on growth and physiological characteristics of Medicago sativa. Chinese Journal of Grassland, 36(2), 20-24.
	[ 史静, 张虎, 尹国丽, 陈伟, 陈本建 (2014). 遮荫对头茬苜蓿生长及生理的影响. 中国草地学报, 36(2), 20-24.]
[21]	Smith H (2000). Phytochromes and light signal perception by plants—An emerging synthesis. Nature, 407, 585-591.
[22]	Wang G, Bai JH, Liu BT (2020). Root traits of six ectomycorrhizal tree species and their relationship with mycorrhizal infection rate in mountainous regions of North China. Acta Botanica Boreali-Occidentalia Sinica, 40, 852-861.
	[ 王港, 白晋华, 刘碧桃 (2020). 华北山地6个外生菌根树种的根属性及其与菌根侵染率的关系. 西北植物学报, 40, 852-861.]
[23]	Wang T, Guo J, Peng YQ, Lyu XG, Liu B, Sun SY, Wang XL (2021). Light-induced mobile factors from shoots regulate rhizobium-triggered soybean root nodulation. Science, 374, 65-71. DOI PMID
[24]	Weller JL, Hecht V, Vander Schoor JK, Davidson SE, Ross JJ (2009). Light regulation of gibberellin biosynthesis in pea is mediated through the COP1/HY5 pathway. The Plant Cell, 21, 800-813.
[25]	Xiao CW, Liu YC (1999). Ecological adaptation of Gordonia acuminata seedlings in different light environments. Acta Ecologica Sinica, 19, 422-426.
	[ 肖春旺, 刘玉成 (1999). 不同光环境的四川大头茶幼苗的生态适应. 生态学报, 19, 422-426.]
[26]	Yang F, Huang S, Gao RC, Liu WG, Yong TW, Wang XC, Wu XL, Yang WY (2014). Growth of soybean seedlings in relay strip intercropping systems in relation to light quantity and red:far-red ratio. Field Crops Research, 155, 245-253.
[27]	Yin DS, Shen HL (2016). Shade tolerance and the adaptability of forest plants in morphology and physiology: a review. Chinese Journal of Applied Ecology, 27, 2687-2698.
	[ 殷东生, 沈海龙 (2016). 森林植物耐荫性及其形态和生理适应性研究进展. 应用生态学报, 27, 2687-2698.] DOI
[28]	Zhan JC, Huang WD, Wang LJ (2003). Research of weak light stress physiology in plants. Chinese Bulletin of Botany, 38(1), 43-50.
	[ 战吉宬, 黄卫东, 王利军 (2003). 植物弱光逆境生理研究综述. 植物学通报, 38(1), 43-50.]
[29]	Zhan JC, Wang LJ, Huang WD (2002). Effects of low light environment on the growth and photosynthetic characteristics of grape leaves. Journal of China Agricultural University, 7(3), 75-78.
	[ 战吉宬, 王利军, 黄卫东 (2002). 弱光环境下葡萄叶片的生长及其在强光下的光合特性. 中国农业大学学报, 7(3), 75-78.]
[30]	Zhao KN, Liu DD (2020). Assessment of plant shade tolerance. Journal of University of South China (Science and Technology), 34(3), 51-59.
	[ 赵康宁, 刘丹丹 (2020). 植物的耐阴性评价. 南华大学学报(自然科学版), 34(3), 51-59.]
[31]	Zhao YY, Zhan HM, Dai XX, Shan DD, Wang TJ (2019). Comprehensive evaluation and screening identification index of shade tolerance of intercropping soybean. Chinese Journal of Oil Crop Sciences, 41(1), 81-91.
	[ 赵银月, 詹和明, 代希茜, 单丹丹, 王铁军 (2019). 云南间作大豆耐荫性综合评价及鉴定指标筛选. 中国油料作物学报, 41(1), 81-91.] DOI
[32]	Zhu YS, Feng H (2010). Effect of low light density on growth angle and morphostructure of tomato seedling function leaves. Chinese Agricultural Science Bulletin, 26(19), 211-215. DOI
	[ 朱延姝, 冯辉 (2010). 弱光对苗期番茄功能叶片生长角度和形态结构的影响. 中国农学通报, 26(19), 211-215.]
[33]	ЦЕЛВНИКЁРЮЛ (Translated by WangSJ) (1986). Physiological Principle on Shade-tolerance of Woody Plants. Science Press, Beijing.
	[ 王世绩 (译) (1986). 木本植物耐阴性的生理学原理. 科学出版社, 北京.]

材料 Material	种质资源类型 Germplasm resource type	选育单位或来源 Breeding institute or resource	秋眠级 Fall dormancy scale
‘WL354HQ’	引进品种 Introduced cultivar	澳大利亚 Australia	3.9
‘巨人201+Z’ ‘AmeriStand 201+Z’	引进品种 Introduced cultivar	美国 USA	2
‘苜蓿王’ ‘Alfaking’	引进品种 Introduced cultivar	美国 USA	2-3
‘阿迪娜’ ‘Adrenalin’	引进品种 Introduced cultivar	美国 USA	4-5
‘南苜701’ ‘SA701’	引进品种 Introduced cultivar	美国 USA	7
‘吉利’ ‘Gea’	引进品种 Introduced cultivar	美国 USA	6
‘劲能5010’ ‘Power 5010’	引进品种 Introduced cultivar	美国 USA	5.4
‘阿尔冈金’ ‘Algonquin’	引进品种 Introduced cultivar	加拿大 Canada	2-3
‘WL343HQ’	引进品种 Introduced cultivar	美国 USA	4
‘四河’ ‘Siriver’	引进品种 Introduced cultivar	澳大利亚 Australia	8
‘维多利亚’ ‘Victoria’	引进品种 Introduced cultivar	加拿大 Canada	6
‘龙牧801’ ‘Longmu 801’	中国育成品种 Chinese bred cultivar	黑龙江省畜牧研究所 Heilongjiang Academy of Animal Husbandry	1-2
‘龙牧803’ ‘Longmu 803’	中国育成品种 Chinese bred cultivar	黑龙江省畜牧研究所 Heilongjiang Academy of Animal Husbandry	1-2
‘草原3号’ ‘Caoyuan 3’	中国育成品种 Chinese bred cultivar	内蒙古农业大学 Inner Mongolia Agricultural University	1-3
‘甘农9号’ ‘Gannong 9’	中国育成品种 Chinese bred cultivar	甘肃农业大学 Gansu Agricultural University	4-5
‘中苜1号’ ‘Zhongmu 1’	中国育成品种 Chinese bred cultivar	中国农业科学院北京畜牧兽医研究所 Institute of Animal Sciences, Chinese Academy of Agricultural Sciences	3
‘中兰2号’ ‘Zhonglan 2’	中国育成品种 Chinese bred cultivar	中国农业科学院和甘肃农业大学联合培育 Chinese Academy of Agricultural Sciences and Gansu Agricultural University	3
‘公农1号’ ‘Gongnong 1’	中国育成品种 Chinese bred cultivar	吉林省农业科学院 Jilin Academy of Agricultural Sciences	1.7
‘敖汉苜蓿’ ‘Aohan Muxu’	地方品种 Local cultivar	内蒙古赤峰 Chifeng, Nei Mongol, China	3
‘陇东苜蓿’ ‘Longdong Muxu’	地方品种 Local cultivar	甘肃庆阳和平凉 Qingyang and Pingliang, Gansu, China	1.2

材料 Material	种质资源类型 Germplasm resource type	选育单位或来源 Breeding institute or resource	秋眠级 Fall dormancy scale
‘WL354HQ’	引进品种 Introduced cultivar	澳大利亚 Australia	3.9
‘巨人201+Z’ ‘AmeriStand 201+Z’	引进品种 Introduced cultivar	美国 USA	2
‘苜蓿王’ ‘Alfaking’	引进品种 Introduced cultivar	美国 USA	2-3
‘阿迪娜’ ‘Adrenalin’	引进品种 Introduced cultivar	美国 USA	4-5
‘南苜701’ ‘SA701’	引进品种 Introduced cultivar	美国 USA	7
‘吉利’ ‘Gea’	引进品种 Introduced cultivar	美国 USA	6
‘劲能5010’ ‘Power 5010’	引进品种 Introduced cultivar	美国 USA	5.4
‘阿尔冈金’ ‘Algonquin’	引进品种 Introduced cultivar	加拿大 Canada	2-3
‘WL343HQ’	引进品种 Introduced cultivar	美国 USA	4
‘四河’ ‘Siriver’	引进品种 Introduced cultivar	澳大利亚 Australia	8
‘维多利亚’ ‘Victoria’	引进品种 Introduced cultivar	加拿大 Canada	6
‘龙牧801’ ‘Longmu 801’	中国育成品种 Chinese bred cultivar	黑龙江省畜牧研究所 Heilongjiang Academy of Animal Husbandry	1-2
‘龙牧803’ ‘Longmu 803’	中国育成品种 Chinese bred cultivar	黑龙江省畜牧研究所 Heilongjiang Academy of Animal Husbandry	1-2
‘草原3号’ ‘Caoyuan 3’	中国育成品种 Chinese bred cultivar	内蒙古农业大学 Inner Mongolia Agricultural University	1-3
‘甘农9号’ ‘Gannong 9’	中国育成品种 Chinese bred cultivar	甘肃农业大学 Gansu Agricultural University	4-5
‘中苜1号’ ‘Zhongmu 1’	中国育成品种 Chinese bred cultivar	中国农业科学院北京畜牧兽医研究所 Institute of Animal Sciences, Chinese Academy of Agricultural Sciences	3
‘中兰2号’ ‘Zhonglan 2’	中国育成品种 Chinese bred cultivar	中国农业科学院和甘肃农业大学联合培育 Chinese Academy of Agricultural Sciences and Gansu Agricultural University	3
‘公农1号’ ‘Gongnong 1’	中国育成品种 Chinese bred cultivar	吉林省农业科学院 Jilin Academy of Agricultural Sciences	1.7
‘敖汉苜蓿’ ‘Aohan Muxu’	地方品种 Local cultivar	内蒙古赤峰 Chifeng, Nei Mongol, China	3
‘陇东苜蓿’ ‘Longdong Muxu’	地方品种 Local cultivar	甘肃庆阳和平凉 Qingyang and Pingliang, Gansu, China	1.2

材料 Material	各指标的耐阴系数 Shade tolerance coefficient of each index
材料 Material	SD	H	PLR	RN	RCT	ASL	LW	PB	LA	SLA	LMR	SMR	RMR	Chl a	Chl b	Chl a+b	Car	Chl a/b
‘WL354HQ’	0.76	0.77	0.51	0.77	0.51	1.16	0.24	0.22	0.34	1.21	1.08	1.13	0.96	0.95	1.11	0.99	0.95	0.89
‘苜蓿王’ ‘Alfaking’	1.14	1.05	1.57	5.43	1.00	1.47	0.92	0.80	1.33	1.29	0.72	0.98	1.13	0.98	0.98	0.98	0.99	1.00
‘维多利亚’ ‘Victoria’	1.24	0.92	1.53	2.26	1.86	1.14	1.79	1.43	1.79	1.19	1.11	1.48	0.58	0.66	0.89	0.71	0.66	0.72
‘阿迪娜’ ‘Adrenalin’	0.92	0.84	0.62	0.66	1.27	1.11	0.31	0.38	0.24	0.77	0.78	1.13	0.95	1.16	1.21	1.17	0.92	0.97
‘南苜701’ ‘SA701’	1.01	1.11	0.89	1.06	1.12	1.17	1.07	0.85	1.01	1.04	1.12	1.08	0.87	1.40	1.30	1.38	1.16	1.07
‘吉利’ ‘Gea’	0.87	0.86	0.62	1.77	1.28	0.98	0.33	0.53	0.46	0.81	0.58	1.06	1.19	0.48	1.36	0.67	0.72	0.52
‘劲能5010’ ‘Power 5010’	0.94	0.82	0.95	0.54	0.88	0.77	0.62	0.69	0.57	1.23	0.92	0.95	1.24	0.98	1.03	0.99	0.97	0.95
‘阿尔冈金’ ‘Algonquin’	0.74	0.54	0.67	0.88	0.77	0.94	0.35	0.34	0.43	1.16	1.01	0.92	1.17	0.94	0.95	0.94	0.95	0.96
‘WL343HQ’	0.99	0.78	0.66	0.92	0.64	0.97	0.35	0.34	0.64	1.23	1.03	1.15	0.72	1.23	1.26	1.23	1.21	0.96
‘四河’ ‘Siriver’	0.91	0.92	1.32	1.35	1.05	0.85	0.61	0.49	0.85	1.45	1.01	1.04	0.88	1.04	1.07	1.04	1.09	0.94
‘巨人201+Z’ ‘AmeriStand 201+Z’	0.78	0.68	0.52	1.01	1.78	1.25	0.25	0.42	0.43	1.72	0.51	0.81	1.94	0.99	1.03	1.00	1.01	0.97
‘龙牧801’ ‘Longmu 801’	1.06	0.70	1.17	1.35	1.57	1.24	1.44	1.00	1.69	1.16	1.16	0.91	0.75	0.91	1.06	0.95	0.87	0.86
‘龙牧803’ ‘Longmu 803’	0.95	0.58	0.91	1.22	0.93	1.13	0.95	0.71	0.57	0.83	0.91	1.01	1.06	1.02	1.19	1.06	0.99	0.91
‘草原3号’ ‘Caoyuan 3’	0.93	1.06	0.75	1.10	1.23	1.22	0.76	0.77	0.80	1.05	1.13	1.10	0.93	0.85	0.99	0.88	0.85	0.84
‘甘农9号’ ‘Gannong 9’	0.64	0.77	0.81	0.54	0.88	0.65	0.39	0.56	0.54	1.30	0.75	1.14	1.00	0.93	1.08	0.97	0.94	0.86
‘中苜1号’ ‘Zhongmu 1’	0.58	0.39	1.00	0.35	0.69	0.60	0.11	0.18	0.10	1.19	1.17	0.71	1.59	0.79	0.97	0.83	0.82	0.81
‘中兰2号’ ‘Zhonglan 2’	0.80	0.90	0.25	1.70	0.56	0.90	0.14	0.21	0.22	1.58	0.71	1.05	0.88	0.98	1.08	1.00	0.98	0.91
‘公农1号’ ‘Gongnong 1’	0.89	1.36	0.29	0.65	0.62	0.92	0.24	0.34	0.34	1.19	0.71	0.93	1.59	0.81	0.86	0.82	0.80	0.90
‘敖汉苜蓿’ ‘Aohan Muxu’	0.57	0.69	1.33	0.48	0.83	1.39	0.32	0.27	0.27	1.30	0.71	1.09	1.03	0.92	0.93	0.92	0.92	0.99
‘陇东苜蓿’ ‘Longdong Muxu’	0.98	0.69	0.91	0.63	0.50	1.18	0.73	0.77	0.51	0.72	0.91	1.13	0.72	0.90	0.99	0.92	0.93	0.92

材料 Material	各指标的耐阴系数 Shade tolerance coefficient of each index
材料 Material	SD	H	PLR	RN	RCT	ASL	LW	PB	LA	SLA	LMR	SMR	RMR	Chl a	Chl b	Chl a+b	Car	Chl a/b
‘WL354HQ’	0.76	0.77	0.51	0.77	0.51	1.16	0.24	0.22	0.34	1.21	1.08	1.13	0.96	0.95	1.11	0.99	0.95	0.89
‘苜蓿王’ ‘Alfaking’	1.14	1.05	1.57	5.43	1.00	1.47	0.92	0.80	1.33	1.29	0.72	0.98	1.13	0.98	0.98	0.98	0.99	1.00
‘维多利亚’ ‘Victoria’	1.24	0.92	1.53	2.26	1.86	1.14	1.79	1.43	1.79	1.19	1.11	1.48	0.58	0.66	0.89	0.71	0.66	0.72
‘阿迪娜’ ‘Adrenalin’	0.92	0.84	0.62	0.66	1.27	1.11	0.31	0.38	0.24	0.77	0.78	1.13	0.95	1.16	1.21	1.17	0.92	0.97
‘南苜701’ ‘SA701’	1.01	1.11	0.89	1.06	1.12	1.17	1.07	0.85	1.01	1.04	1.12	1.08	0.87	1.40	1.30	1.38	1.16	1.07
‘吉利’ ‘Gea’	0.87	0.86	0.62	1.77	1.28	0.98	0.33	0.53	0.46	0.81	0.58	1.06	1.19	0.48	1.36	0.67	0.72	0.52
‘劲能5010’ ‘Power 5010’	0.94	0.82	0.95	0.54	0.88	0.77	0.62	0.69	0.57	1.23	0.92	0.95	1.24	0.98	1.03	0.99	0.97	0.95
‘阿尔冈金’ ‘Algonquin’	0.74	0.54	0.67	0.88	0.77	0.94	0.35	0.34	0.43	1.16	1.01	0.92	1.17	0.94	0.95	0.94	0.95	0.96
‘WL343HQ’	0.99	0.78	0.66	0.92	0.64	0.97	0.35	0.34	0.64	1.23	1.03	1.15	0.72	1.23	1.26	1.23	1.21	0.96
‘四河’ ‘Siriver’	0.91	0.92	1.32	1.35	1.05	0.85	0.61	0.49	0.85	1.45	1.01	1.04	0.88	1.04	1.07	1.04	1.09	0.94
‘巨人201+Z’ ‘AmeriStand 201+Z’	0.78	0.68	0.52	1.01	1.78	1.25	0.25	0.42	0.43	1.72	0.51	0.81	1.94	0.99	1.03	1.00	1.01	0.97
‘龙牧801’ ‘Longmu 801’	1.06	0.70	1.17	1.35	1.57	1.24	1.44	1.00	1.69	1.16	1.16	0.91	0.75	0.91	1.06	0.95	0.87	0.86
‘龙牧803’ ‘Longmu 803’	0.95	0.58	0.91	1.22	0.93	1.13	0.95	0.71	0.57	0.83	0.91	1.01	1.06	1.02	1.19	1.06	0.99	0.91
‘草原3号’ ‘Caoyuan 3’	0.93	1.06	0.75	1.10	1.23	1.22	0.76	0.77	0.80	1.05	1.13	1.10	0.93	0.85	0.99	0.88	0.85	0.84
‘甘农9号’ ‘Gannong 9’	0.64	0.77	0.81	0.54	0.88	0.65	0.39	0.56	0.54	1.30	0.75	1.14	1.00	0.93	1.08	0.97	0.94	0.86
‘中苜1号’ ‘Zhongmu 1’	0.58	0.39	1.00	0.35	0.69	0.60	0.11	0.18	0.10	1.19	1.17	0.71	1.59	0.79	0.97	0.83	0.82	0.81
‘中兰2号’ ‘Zhonglan 2’	0.80	0.90	0.25	1.70	0.56	0.90	0.14	0.21	0.22	1.58	0.71	1.05	0.88	0.98	1.08	1.00	0.98	0.91
‘公农1号’ ‘Gongnong 1’	0.89	1.36	0.29	0.65	0.62	0.92	0.24	0.34	0.34	1.19	0.71	0.93	1.59	0.81	0.86	0.82	0.80	0.90
‘敖汉苜蓿’ ‘Aohan Muxu’	0.57	0.69	1.33	0.48	0.83	1.39	0.32	0.27	0.27	1.30	0.71	1.09	1.03	0.92	0.93	0.92	0.92	0.99
‘陇东苜蓿’ ‘Longdong Muxu’	0.98	0.69	0.91	0.63	0.50	1.18	0.73	0.77	0.51	0.72	0.91	1.13	0.72	0.90	0.99	0.92	0.93	0.92

主成分 Principal		PC1	PC2	PC3	PC4	PC5
特征向量 Eigenvector	SD	0.774	0.324	0.222	-0.209	-0.032
特征向量 Eigenvector	H	0.235	0.160	0.288	-0.666	-0.425
	PLR	0.614	0.113	0.182	0.525	-0.084
	RN	0.249	0.050	0.853	-0.045	0.051
	RCT	0.617	-0.084	0.419	0.045	0.488
	ASL	0.377	0.280	0.612	-0.082	-0.200
	LW	0.924	0.188	-0.096	0.172	0.085
	PB	0.944	0.043	0.011	0.086	0.090
	LA	0.869	0.201	0.030	0.194	0.176
	SLA	-0.677	0.171	0.376	0.230	0.107
	LMR	0.389	0.273	-0.693	0.439	-0.033
	SMR	0.632	0.150	-0.264	-0.428	-0.262
	RMR	-0.582	-0.410	0.462	0.159	0.180
	Chl a	-0.259	0.946	-0.020	0.040	0.017
	Chl b	-0.087	0.375	-0.208	-0.547	0.651
	Chl a+b	-0.255	0.942	-0.058	-0.062	0.134
	Car	-0.398	0.865	0.035	0.036	0.098
	Chl a/b	-0.348	0.779	0.207	0.279	-0.310
特征值 Eigenvalue		5.845	3.880	2.240	1.563	1.178
贡献率 Contribution rate (%)		32.472	21.554	12.442	8.683	6.543
累计贡献率 Cumulative contribution rate (%)		32.472	54.026	66.468	75.151	81.694