青藏高原栽培大麦千粒重空间分布格局及其与环境因子的关系

Relationship between spatial distribution pattern and factors affecting weight per thousand seeds of cultivated barley in Qinghai-Tibet Plateau

千粒重是大麦产量的重要构成因素之一。青藏高原强辐射、低温、干旱的生态环境孕育了现代农业所急需的大麦种质资源,但是迄今为止尚未见到有关青藏高原栽培大麦WTS与环境因子关系的系统性研究报道。为了揭示青藏高原栽培大麦千粒重的空间分布规律,探明不同环境因子对青藏高原栽培大麦千粒重(WTS)积累的影响程度,利用83个样点的地理、气候、土壤因子数据,研究了青藏高原栽培大麦WTS的分布特征。结果表明:(1)在地理水平方向上,青藏高原栽培大麦WTS总体呈现出斑块状交错分布的格局,形成了以西藏曲水、堆龙德庆、白朗、乃东、日喀则、扎囊、贡嘎、加查、达孜、谢通门、拉孜、定日为中心的青藏高原西南部和青海海晏、门源、刚察为中心的青藏高原东北部等2个栽培大麦WTS高值区;(2)在地理垂直方向上,栽培大麦WTS的变化呈现出"N"型分布格局,即在海拔3600.0—3900.0m和4500.0m以上形成2个WTS高值区,这2个海拔区间栽培大麦WTS分别为(49.6815±10.0764)g和(47.9500±0.1732)g;(3)影响栽培大麦WTS的环境因子从大到小的顺序是抽穗-成熟期降水量>土壤速效钾含量>分蘖-拔节期日照时数>抽穗-成熟其平均气温>抽穗-成熟期日照时数>拔节-抽穗平均气温日较差>地理经度。

Weight per thousand seeds （WTS） is an important quality character of barley grain. In recent years, some researchers have shown that WTS is affected by genetic factors, as well as by its cultivation and environmental conditions. However, the effects of different environmental factors on barley WTS remain unclear. In addition, although previous studies have mostly been conducted at several sites, large-scale studies have not systematically addressed the relationship between cultivated barley WTS and environmental factors. Moreover, with a large number of hull-less barley varieties or resources being required on an urgent basis for modern agriculture development in an environment of high radiation, low temperature, and drought, Qinghai-Tibet Plateau is an important region for growing hull-less barley in China. However, until now, the relationship between barley WTS and environmental factors in Qinghai-Tibet Plateau has not been reported. Therefore, the present study investigated the distribution of cultivated barley WTS characteristics in Qinghai-Tibet Plateau using geography, climate, soil, and agronomy data from 83 sampling sites. The aim of this study was to identify the relative effects of different environmental factors on WTS, to clarify the relationship between the distribution of barley WTS and environmental factors, and to explicitly assess acclimation of WTS of barley varieties planted in different areas to the environment. The results showed that （1） WTS exhibited a macrocosm pattern of spatial distribution along the horizontal direction in Qinghai-Tibet Plateau, with staggered patches of different values and an N-shaped tendency. In addition, two regions of higher WTS （south-western and north-eastern） included the counties of Qushui, Duilongdeiqin, Naidong, Shigatse, Zhanang, Gongga, Jiacha, Dazi, Qiongjie, Lazi, and Dingri in Tibet and Haiyan, and Mengyuan and Gangcha in Qinghai Province. （2） Along the vertical direction, GSC distribution exhibited a pattern with double peaks, with two higher value zones between the altitudes from 3600.0 m to 3900.0 m and that above 4500.0 m with average WTS values of （49.6815±10.0764） g and （47.9500±0.1732） g, respectively. （3） The effect of the magnitude of environmental factors on WTS followed an order of precipitation during the growth period from heading to maturation 〉 soil available K content 〉 sunshine hours during the growth period from tillering to elongation 〉 average temperature during the growth period from heading to maturation 〉 sunshine hours during the growth period from heading to maturation 〉 average diurnal temperature range during the growth period from elongation to heading 〉 longitude.