نشریه نهال و بذر
سال بیست و نهم شماره 4 (زمستان 1392)

Study of physiological traits and the relationship between these traits and grain yield in drought stress conditions can be useful to identify effective physiological traits involving in resistance to drought stress. In order to study these traits، parameters such as gas exchange، water status، flag leaf characteristics، chlorophyll content index، grain yield and thousand grain weight were measured in twenty bread wheat genotypes (18 lines، together with Sardari and Azar 2 cultivars). The experiment was conducted in rainfed condition at Agricultural Research Station of Gheidar، Zanjan، Iran. Mean comparisons showed that line No. 4 and cultivar Azar 2 had the highest grain yield among the genotypes. Genotypes having lower internal CO2 concentration and higher thousand grain weight، produced higher yield. Decrease in photosynthesis was mainly due to non-stomatal limitations، and high grain yield was not related to leaf relative water content. Cluster analysis and principal component analysis based on measured traits classified genotypes into three separate clusters. Based on the overall results of present study، genotypes No. 2، 4، 8، 10، 13، 17، 6 and 18 were superior than the others under rainfed condition.

To study cold tolerance (CT) of thirteen chickpea advanced lines together with Jam cultivar as check and relationship between CT and agronomic traits، two experiments were conducted under controlled and field conditions during 2010-2011 cropping season at Maragheh Dryland Agricultural Research Station. The first experiment was conducted under natural condition (fall sowing at field)، using randomized complete block design with four replications. In the second experiment، seeds of genotypes were planted in concrete boxes with one meter height from soil level، using nylon covers to prevent snow fall on planting beds during winter. Percentage of genotypes cold injeries was assessed in early spring after ending of cold. Under field condition، there were significant differences among genotypes for all studied traits. There were also significant differences among genotypes for no snow cover cold (Base cold: BC) tolerance in concrete boxes. Line FLIP 00-84C with 87% of survived plants under field condition and 23% of BC (-20ºC for two days) damage، was the most tolerant line. There was negative and significant correlation (r = -0. 56) between CT under controlled condition and number of survived plants after winter in field condition. There were also significant positive correlation between BC damage and percentage of cold damage of plants after the first and second severe colds (r = 0. 56 and r = 0. 50، respectively). In conclusion، there was a conformity between results obtained from controlled and field conditions، therefore box planting method could be recommended as a new and reliable method for evaluating cold tolerance in chickpea germplasm

Thirty five morphological traits were evaluated in seven local walnut genotypes Jamal، Damavand، B21، K72، Z53، Z60، Z67 and eight foreign cultivars Chandler، Pedro، Hartley، Ronde de Montignac، Serr، Lara، Vina and Franquette in 2008 and 2009. Related to tree traits، a moderate variation in characters were observed، but there were higher variations in tree vigor and bearing habit. Leaf characteristics showed lower variation، while leafing time، showed very high variation so that there were 21 days difference between the earliest and latest cultivars. Pistillate flower receptivity and pollen shedding period order، could separate the genotypes. According to dichogamy، two genotypes were protogynous، one cultivar was homogamus tend to protogynous and the others were protandreous. Time of fruit ripening was also highly variable. There were 42 days difference between the earliest and latest cultivars. Fruit shapes in longitudinal section through and perpendicular suture had high potential to distinct genotypes. Fruit and kernel size، and kernel percent also showed high variation. In conclusion، cultivars Chandler، Pedro and Hartley showed to be superior based on leafing date، lateral fruitfulness and nut and kernel characteristics. Cultivars Ronde de Montignac and Franquette had good pollen shedding period for these three cultivars. Local cultivar Jamal had better performance and Damavand showed good pollen shedding period appropriate for it.