Agronomic assessment of cold tolerant chickpea (Cicer arietinum L.) genotypes in fall sowing at Mashhad conditions

Studies on the fall-winter sowing of chickpea were commenced in 1974-75 at Mediterranean regions. For example, Singh et al, (1997) studied some chickpea cold and ascochyta blight tolerant genotypes in fall-winter sowing for 10 years (1983-1993) on three regions in Syria and Lebanon under rain-fed conditions. The mean of seed yield for 10 years in the fall-winter sowing was 1686 kg.ha-1 that showed 70% of increase comparing to seed yield in spring sowing with 994 kg.ha-1. Biological yield in fall-winter sowing had the same increase record comparing with spring sowing, too. They declared that the extended vegetative period in fall-winter sowing than spring sowing was the cause of this result. Also, studies on fall sowing of chickpea in Iran have shown that significant enhancement of seed yield compared to spring sowing has arisen from exploiting of sufficient water and extending of a growth period in fall sowing. Regarding to the results of previous studies on fall-winter sowing of chickpea that demonstrated possibility of this type of sowing in cold areas, this experiment was performed in order to evaluate yield and yield components of 152 other chickpea genotypes in fall sowing.
This study was carried out in three years of 2002-2003, 2003-2004 and 2004-2005 at the Experimental Field of College of Agriculture, Ferdowsi University of Mashhad, north-eastern Khorassan state of Iran. This study was performed in rainfed conditions with only two times irrigation at planting stage and 20 days after that. In the first year (2002-2003), 46 chickpea genotypes (30 cold tolerant accessions resulted from previous studies at Mashhad and some genotypes from ICARDA and Canada) were planted based on Randomized Complete Block Design with three replications. During this year, cold injury caused complete loss so, in the next two years by adding of 106 other accessions, totally, 152 chickpea genotypes with 4 checks were evaluated based on the Augmented Preliminarily Design. The seeds of genotypes were attained from Mashhad Chickpea Collection (MCC), Research Center for Plant Sciences, Ferdowsi University of Mashhad. The seeds of each genotype in all trials were sown in plots containing one row with a length of 2.5 meter. The distance between seeds on the row was 0.1 meter and rows were placed 0.5 meter apart. In the second and third trials, genotypes were categorized according to their seed yield amounts to several groups and some statistical indices such as mean, standard deviation and range were calculated on their measured quantitative traits (such as seed yield, biological yield, and yield components). Based on data analysis, existing of significant differences among genotypes and controls were studied between them. Finally, superior genotypes were selected and introduced for continuing of investigations at future.
In the first year, the hard, cold and freezing temperatures occurred after emerging of seedlings, repeatedly and then all plants were lost. There were 69 days with freezing temperatures through the period of planting to late winter. The lowest temperature through this period was -12.8°C that occurred in November and December. Based the on results, in the next two years, there were significant differences (P≤0.05) among genotypes with each other and with checks in yield, yield components and plant height. In the second year (2003-2004), the range of seed yield among the first yield group (39.5% of all genotypes) was from 251 to 622 g.m-2, while in the third year (2004-2005) this range among the first yield group (20% of all genotypes) was from 254 to 442 g.m-2. In the second and third years, the highest survival percent, meaning among all five groups was observed in the first groups. Totally, 20 chickpea genotypes with the most yields for each year were selected and introduced for the next studies.
Regarding to rainfed conditions, the higher seed yields in the second year comparing to the third year can be related to greater precipitations in this trial (271 mm) compared to the third (202 mm), as well as better distribution of rainfall in the second year coinciding with the vegetative growth period. Occurrence of higher temperatures at the end of the growing season in the third year also could be a limiting factor for reproductive growth of chickpeas. It seems that the existing of only one genotype (MCC798), communally in two years among 20 superior genotypes, revealed this fact that these genotypes respond to various environmental circumstances, differently. Regarding to mean of seed yield of chickpea in Iran (410 kg.ha-1), achieving of seed yield records of 3800 to 6220 kg.ha-1 at the second trial and 2740 to 4420 kg.ha-1 at the third trial in this study that were obtained from next to 40 chickpea genotypes, reveals a promising potential for a fall sowing of chickpea in Mashhad. However, concerning about this fact that the temperature in the two years of this study did not drop less than -13.2°C on the second trial and -9.2°C on the third, it is suggested to investigate of phenological and morpho-phisiological aspects of these genotypes more, especially in colder areas in order to be sure of their cold tolerance, sustainably. Finally, 20 chickpea genotypes with the most yields for each year (totally 39 genotypes) were selected and introduced for the next studies. Considering the importance of field investigations, these results can be completely efficient for continuing research and development programs on the subject of chickpea cold tolerance in the present and the future.