| Results and Discussion The precentage heterotic values over mid parent (MP) as well as better parent (BP) in single cross and three-way cross hybrids are presented in Table 1 and 2 respectively. In general, it appears that good number of three-way hybrids exhibited significantly positive heterosis for yield and it's few important components over mid and better parents. This is quite expected because the parents involved in all the single crosses were unadapted types. However, the use of a well adapted parent in 3-way cross, helped in recovery of desiriable agronomic characters like ear weight, 1000-grain weight and grains per ear. Similarly in case of yield per plant, of the 20 crosses, 4 crosses in F1 and 7 crosses in threeway hybrids exhibited significant heterosis over better parent. On the contrary, for flag leaf area, the number of crosses indicated significant heterosis over better parent were more in single crosses than three-way cross hybrids (8 in SC and 4 in TWC). An ideal three-way hybrid combination would be one which show an increased heterosis over single cross. Many such combinations were identified and listed in Table 3. It is interesting to note that significantly positive heterosis was observed in a number of threeway hybrids although in many of the corresponding single crosses the heterosis was non-significant or negative. For grains per ear, 7 hybrids which were showing low heterosis in F1 indicated high heterosis in TWC. Of these crosses, T. pyramidale x Sel. 389 was showing significantly negative heterosis over both mid and better parents, exhibited the highest heterosis (87.92%) in TWC. In case of 1000-grain weight ten F1 crosses involving T. dicoccum, T. polonicum and T. pyramidale showed non-significant heterosis. The threeway crosses between these F1 with JNK-4w-184 indicated significant heterosis. Similarly non-significant heterosis was observed over mid parent for the ear weight in a number of F1 hybrids (14 out of 20 crosses) between five species (A,B, C, D and E) and four durum cultivars (E. F, G and H). But in combination with third parent (I) heterosis was significant over mid parent (all the 20 three-way crosses) and better parent (18 out of 20 crosses). As regards to flag leaf area, the SC cross T. dicoccum x A206 showed negative heterosis over both the parents, while the same cross in three-way combination recorded the significant and positive heterosis. Considering grain yield per plant, three crosses namely, T. turgidum-45 x Sel. 389, T. pyramidale x NP404 and T. dicoccum x A206 did not show significant heterosis but these crosses with JNK-4w-184 recorded the significant and positive heterosis over both the parents. Besides, this study has also shown that there were some crosses showed significantly positive heterosis over both parents in single crosses as well as three-way hybrids simultaneously for all the characters studied (Table. 3). Emphasising all the characters at a time, it appeared that six three-way hybrids viz., (T. dicoccum x A206) JNK-4w-184; (T. dicoccum x NP404) JNK-4w-184; (T. dicoccum x Sel. 389) JNK-4w-184; (T. polonicum x A206) JNK-4w-184; (T. tugidum-45 x Sel. 389) JNK-4w-184; (T. pyramidale x Sel. 389) JNK-4w-184, would be studied further for exploiting better recombinants by virtue of their favourable response for important yield components as well as yield. |
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