Genetic control of physiological traits associated to low temperature growth in sunflower under early sowing conditions

Clémentine Allinne,Pierre Maury,Ahmad Sarrafi,Philippe Grieu

doi:10.1016/j.plantsci.2009.07.002

Abstract

This study was conducted to identify physiological traits associated with cold tolerance in sunflower and to identify the genomic regions involved in their variation. A population of 98 recombinant inbred lines (RILs) and their two parents were sown in the field as usual sowing date (control) and one or two months earlier (long-term low temperature treatments). A trait commonly used to underlying cold tolerance related to the degree of membrane damage, as well as traits associated with growth capacity (chlorophyll content, potential photochemical efficiency of photosystem II and plant dry weight) and finally those reflecting acclimation mechanism to stress conditions (osmotic potential at full turgor, and specific leaf area) have been investigated at early development stages. Significant differences were observed among the three sowing dates for all traits. Chlorophyll content and specific leaf area are genetically associated with cold tolerance. Genetic gains were observed for chlorophyll content and osmotic potential traits in some of early sowing dates, which suggest that they could be used for cold tolerance in breeding programs. QTL analyses show that several putative genomic regions are involved in the variation of the physiological traits studied under low temperature. Major QTLs for cold tolerance associated with SSR markers such as ORS331_2 for the cell membrane stability should be checked in several environments to see if they can be used in marker-assisted selection programs.

Highlights

Sunflower is one of the most important oil crops worldwide
The objectives of this research are to study a set of physiological traits associated with cold tolerance, to understand which are affected in the first development stage in sunflower subjected to early sowing associated with long-term low temperature exposure and to analyze the genetic basis of low temperature tolerance in sunflower
This indicates that the recombinant inbred lines (RILs) are representative of possible genotypic combinations of the two parents for the studied traits, as it was previously reported by Poormohammad Kiani et al [30], for the water status and the osmotic adjustment of sunflower under two water treatments

Summary

Introduction

Sunflower is one of the most important oil crops worldwide. This summer crop is mainly cultivated under rather high temperature. Water deficit stress which can take place during critical periods of flowering and grain filling induces yield decline [1]. Two main strategies have been studied to maximize the sunflower production under drought stress conditions. The first way is to improve the drought tolerance of sunflower cultivars [2,3]. Sowing is the second way to avoid the critical water stress period [4]. Authors have shown that early sowings improve the water availability [7] and increase the yield of the crop [8,6]. Early sowing compared with conventional sowing is associated with long-term low temperature exposure during first stages of development in sunflower

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