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Less attention had been given to the performances of three-way crosses and its comparative advantages of these hybrids over single crosses. This study was carried out to evaluate the performances of three-way crosses in comparison to single crosses for yield and related agronomic traits and to estimate the magnitude of heterosis. The trial was laid out in a simple alpha lattice design of 10 × 6 for lines, 6 × 5 for single crosses (SC), and 9 × 5 for three way-crosses and planted in adjacent plots in the 2019 cropping season in three locations namely Ambo, Abala-Farcha and Melkassa. Single cross hybrids showed a highly significant (P

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The objectives were to study the combining ability of 30 lines from the maize breeding program of Instituto Agronômico, Sao Paulo State, (SP), Brazil, in top crosses schemes. The 30 lines and two testers (single cross hybrids) were crossed to obtain the 60 top crosses that were evaluated, with three commercial hybrids (checks), in two locations, Mococa and Campinas, in 2001/02, using a randomized complete block design with three replications. The following agronomic traits were evaluated: Plant height (PH), ear height (EH), lodged and broken plants (Ld + Br), and grain yield (GY) corrected to 14% moisture. The combining ability of the lines was estimated according to the Griffing’s Method 2 (1956), adapted for partial diallels. The Mean Squares presented a significant (P < 0.01) effect for Lines and Lines /Tester in all the characters, except (Ld + Br) in Mococa, showing additive effects in their control. The cross effects were significant (P < 0.01) for all characteristics in Mococa and only for EH and GY in Campinas. The interaction effect (Tester x Line) was significant in Mococa (P < 0.01), indicating that non-additive effects for PH, EH and GY were important too. A significant number of three way cross presented GY similar to the checks. The lines L 10, L 156, L 126, L 111, SLP 103 and IP 330 were outstanding for general combining ability and should be useful in maize breeding programs in tropical conditions.

Less attention had been given to the performances of three-way crosses and its comparative advantages of these hybrids over single crosses. This study was carried out to evaluate the performances of three-way crosses in comparison to single crosses for yield and related agronomic traits and to estimate the magnitude of heterosis. The trial was laid out in a simple alpha lattice design of 10 × 6 for lines, 6 × 5 for single crosses (SC), and 9 × 5 for three way-crosses and planted in adjacent plots in the 2019 cropping season in three locations namely Ambo, Abala-Farcha and Melkassa. Single cross hybrids showed a highly significant (P<1%) variation for grain yield, plant height, ear height, and ear length at three locations. These single cross hybrids had showed also a highly significant genotype by environment interaction (P < 1%) for grain yield, plant height, ear height and kernel per ear. Regarding three-way crosses, there was a significant variation (P<5%) on grain yield in Ambo and Melkassa but on ear height and rows per ear in Abala-Faracho. The genotype × environment interaction was significantly varied for grain yield, ear height and ear length. In the comparison, 80% crosses in Ambo, 73% in Abala-Faracho and 67% in Melkassa showed that three-way crosses were better in their performance than that of their respective single crosses. On the other hand, the single crosses that out-performed their respective three-way crosses were higher in Melkassa than Abala-Faracho and the least were reported from Ambo. Similarly, the maximum better and mid-parent heterosis was from single cross 1(769%) in Ambo and single cross 7 (104%) in Melkassa whereas TWC 14 (52%) and TWC 24 (78%) were the highest better and mid-parent heterosis, respectively in Ambo, TWC1 (56%), and TWC30 (25%) were the highest BPH, and MPH, respectively in Melkassa., (© 2023 The Authors.)

Male-sterility systems combined with insect-mediated cross-pollination in soybean [Glycine max (L.) Merr.] have been shown to produce large quantities of hybrid seed, which can be useful for studying heterosis and agronomic performance in different population types. The procedure was used to obtain large quantities of hybrid seed for replicated yield trials. The objective of our study was to evaluate agronomic performance of soybean single, three-way, four-way, and five-way crosses, and three backcross generations (BC1, BC2, and BC3) to estimate heterosis for yield and other agronomic traits. Parental genotypes were male-sterile, female-fertile lines, selected for excellent insect pollinator attraction, crossed to a group of male parents selected for their agronomic performance. In 2003, F1 seed of single crosses were evaluated in replicated experiments at two locations in Iowa and one location in Indiana. In 2004, three-way crosses and BC1 populations were evaluated at one location in Iowa. In 2005, hybrid seed of single, three-way, and four-way crosses, BC1, and BC2 populations of eight families were planted at one location in Iowa. In 2006, the five-way crosses and BC3 populations were planted at one location in Iowa. In all experiments, hybrids and parents were evaluated. Results showed a range in mid-parent heterosis values (MPH) for yield from -35% to +42%, and in high-parent heterosis (HPH) from -44% to +42%. For yield, backcross populations had higher heterosis estimates than the other population types. For seed protein content, mean MPH ranged from -1% to +7%, and mean HPH from -4% to +7%. For oil content, mean MPH ranged from -10% to +6%, and mean HPH from -13% to +3%. Negative heterosis values were observed, indicating that a large number of different parental combinations need to be evaluated to identify the superior heterotic combinations. These evaluations will determine the feasibility of hybrid soybean production for commercial purposes. [ABSTRACT FROM AUTHOR]