Evaluation of Correlation Coefficient and Factor Analysis for Seed Yield, Some Phenological and Morphological Traits of Fenugreek (Trigonella foenum-graceum) Landraces in Drought Conditions

Fenugreek (Trigonella foenum-graecum) is an annual plant belong to Fabaceae and is one of the traditional medicinal plants worldwide. It can provide seed and protein suitable for human's nutrition as well as animals. Water scarcity is a key threat in twenty-first century. On average, 40% of the world land surface are drylands, while this surface area is 90% in Iran. Supplying water requirement of Fenugreek through irrigation is an important factor affecting its growth and yield.

The experiment was conducted as split plots based on randomized complete block design with three replications at the Research Farm, Faculty of Agriculture of shahed university, Iran, in 2014 and 2016. The main-plot was three levels of drought stress, included severe drought stress (20% field capacity), moderate drought stress (40% field capacity), mild drought stress (60% field capacity) and non-drought stress (80% field capacity) as control. Sub plots were nine Fenugreek ecotypes including Neyshabur, Shirvan, Mashhad, Tabriz, Roudsar, Isfahan, Hamadan, Ardestan and Shiraz. At maturity, and the plants were harvested from the soil surface and the plant height and number of lateral branches, number of pod per plant, number of seed per pod, 1000 seed weight, seed yield and aboveground biological yield were measured in the lab. Statistical analysis carried out using SPSS version 16 software. Significant difference was set at p ≤ 0.05 by using Duncan’s multiple range test.

Results of stepwise regression showed that the traits including biomass, harvest index, branch length and number of pods per plant explained 96.7% of grain yield variation, respectively. Factor analysis for morphologic, yield and component yield traits showed the first three independent factors explained 93.48% of total variance in all genotypes. Days to maturity with 36.47% of total variance had the highest amount in the first factor, while, number of seeds per plant and seed yield with 29.74% and 27.07% of total variance were ranked as second and third factors, respectively. Cluster analysis by Ward’s minimum variance, clustered ecotypes into three groups including 1- Isfahan, Ardestan, Hamedan and Shiraz 2- Mashhad and Tabriz 3- Shirvan, Rudsar and Neyshabur. The results showed that, the plant height, Internode length, number of pod and seed per plant, 1000 seed weight, biological and seed yield and harvest index significantly affected by drought stress and ecotypes. The highest plant height, number of pods, 1000 seed weight, biomass, seed yield and harvest index was recorded in Shirvan ecotype while, the longest day to maturity and height of first pod were observed in Neyshabur ecotype at 80% FC. The highest plant height, the first formed pod, 1000 seed weight, seed yield and harvest index in Shirvan ecotype were observed in the 40% FC.ConclusionDrought stress reduced all studied traits in all Fenugreek ecotypes in this experiment. For seed yield, the performance of shirvan ecotype was the best compare to other ectypes in control and mild and moderate stress condition. The highest distance of the first pod from the soil surface in the control condition was observed in the Neyshabur ecotype but in the moderate stress condition in Shirvan ecotype, this trait is important for the mechanized cultivation. Based on the results, there is a reliable variation amongst different Iranian Fenugreek ecotypes and they could use for breeding programs against drought stress. It also seems that Shirvan ecotype of Fenugreek can be considered for stable seed and biomass production under moderate drought stress and normal conditions.