Table 3.

Summary of phenotypic data

Group	Breeds	Abbreviation	Sample size	Average annual egg numbern	Totalb
High productivity	White Leghorna	WL	100	315	220
	Dwarfc	DW	60	280
	Rhode Island Redd	RIR	60	310
low productivity	Beijing Youe	BY	42	110	222
	Henan Gamef	HN	13	100
	Xishuangbanna Gameg	XS	10	110
	Turpanh	TU	11	70
	Zhangzhou Gamei	ZZ	10	80
	Luxi Gamej	LX	10	40–60
	Tibetank	TB	42	40–80
	Hongshanl	HS	42	116
	Taihe Silkiesm	SK	42	110
Total	–	–	–	–	442

^aWhite Leghorn came from two different groups. Among them, 40 samples obtained from the Experimental Chicken Farm at the China Agricultural University, 60 samples obtained from Beijing Yanqing Commercial Layer Breeding Company. Their abbreviations are WL_CAU and WL_YQ, respectively

^bRegarding the sample size, we tried to make the ratio between case and control was 1:1 to avoid the large number difference between the two groups interfering the results

^cDwarf chickens obtained from Beijing Yanqing Commercial Layer Breeding Company

^dRhode Island Red obtained from Beijing

^eBeijing You chickens obtained from Beijing

^fHenan Game obtained from Henan province

^gXishuangbanna Game obtained from Xishuangbanna, Yunnan province

^hTurpan obtained from Turpan, Xinjiang

ⁱZhangzhou Game obtained from Fujiang province

^jLuxi Game obtained from Shandong province

^kTibetan obtained from four different places, including the Experimental Chicken Farm at the China Agricultural University, Nimu, Tibet, Naidong, Tibet and Lingzhi, Tibet

^lHongshan chickens obtained from Hubei province

^mTaihe Silkies chickens obtained from the Experimental Chicken Farm at the China Agricultural University

ⁿRefer to the poultry genetic resources in China