Agronomic Characterization of Tunisian Spontaneous Oat ... - Iresa

Genetic potential and heritabilities.For the slow-leaf rusting criteria, thelatency period (LP) showed the greatestheritability (0.9998) (Table 4). The othercharacters AUDPC, UCm and US gaveheritabilities of 0.9917, 0.9731and 0.9670respectively. For the agronomic traits, 100seed-weights (100SW) showed the greatestheritably (0.9969), however heritabilitiesfor the other characters varied between0.8214 (for DM) and 0.9936 (for LW). It isclear that the heritability of all theagronomic and pathological criteria arehigh. The traits with high H² are the mostuseful in breeding.Table 4. Variance components for the measured traits in Avena spp. and the calculatedheritabilities.Character MSG MSB MSE Fp H²DHFSPLSLLLWPHDMSSSP100SWAUDPCUCmUSLP279.904119.91153.7651126.7335106.4841814.7295374.06442.53407.5212115.69312102422.81481.324812.7878306.82111679.4246119.469322.5908760.4010638.90474888.37702244.386715.2040645.1273694.158912614536.92887.949076.72691840.926720.40520.38580.04084.90960.676215.794966.79490.11000.73170.354517535.500612.96520.42170.004313.7173*51.6096*92.2460*25.8130*157.4548*51.5817*5.6002*23.0263*10.2780*326.3119*119.8952*37.1241*30.3195*70328.9647*0.92710.98060.98920.96130.99360.98060.82140.95660.90270.99690.99170.97310.96700.9998MSG: mean square genotype; MSB: mean square block; MSE: error mean square; Fp: Ftest of population effect.*Population effect significant at P < 1‰.Classification of accessions. In orderto improve the hierarchical cluster analysisof populations, we included only the 3 firstprincipal components, accounting for 76%of the total inertia; and the matrix ofEuclidian distances calculated from thepopulation mean PCA scores (data notshown). The clustering method appliedwas based on the regrouping ofpopulations at similarity level estimated byEuclidian distances (Fig. 1). Cutting thetree at distance 30 gives three groups:Group 1 contains the spontaneousaccession AC1 and AC5 resistant to oatcrown rust, Group 2 includes the fourspontaneous accessions AC3, AC4, AC6,and AC2, the cultivar Av.95 selected forits agronomic characteristics forms thethird group.In order to identify the characters ableto discriminate between these 3 groups, themeans and standard deviations of traitswere calculated for each groupindependently. Mean comparisons betweengroups show significant differences for allthe traits, however fertile stem per plantand spikelet per panicle were notsignificantly different between the groups2 and 3 (Table 5). Group 1 possesses thehighest means for 7 traits: leaf per stem,leaf length, leaf width, plant height, daysto maturity, days to heading and 100-seedweight. Group 2 retains the highest meanof only the number of seeds per spikelet.Tunisian Journal of Plant Protection 5Vol. 3, No. 1, 2008