Universidad Nacional de La Plata
Maize-Balsas teosinte and maize-Guatemala teosinte hybrids: inheritance of plant traits
--Víctor Raúl Corcuera
In connection with the study of the possibilities offered by Balsas teosinte (Zea mays ssp. parviglumis var. parviglumis) and Guatemala teosinte (Z. luxurians) as wild genetic resources of maize (Z. mays ssp. mays), six plant traits were measured in F1 and F2 progenies derived from crosses between maize x Balsas teosinte and maize x Guatemala teosinte. The same traits were also measured in their respective parents, and in all the cases on the basis of individual plants.
The traits measured in the different populations were the following: 1) plant height (PH), 2) stalk diameter (ST), 3) number of leaves per tiller (NLT), 4) leaf width (LW), 5) leaf length (LL) and 6) number of tillers per plant (NTP).
Taxonomically, maize and Balsas teosinte are grouped in Section Zea whilst Guatemala teosinte belongs to Section Luxuriantes (Doebley and Iltis, 1980). Maize has short and narrow leaves, few tillers per plant, and is not very tall, with a low number of leaves and great stalk diameter compared to teosinte species.
The descriptors evaluated are quantitatively inherited, and according to the results shown in Tables 1 to 4, the following can be deduced:
1) Stalk diameter and plant height average values found both in F1 and F2 progenies are very similar to the mid-parent value. This fact denotes that these traits are controlled by genes with additive effect.
2) The same phenomenon is observed when one analyzes what happens with the trait, number of leaves per tiller.
3) Maize-Balsas teosinte and maize-Guatemala teosinte F1 and F2 hybrids show leaves as short and wide as maize. This fact lets us deduce that maize is dominant over teosinte species for these traits.
4) Finally the F1 and F2 progenies derived from both crossings show number of tillers lower than the mid-parent, and displaced to the left side (maize). Thus it could be said that maize is not completely dominant for this trait (dominance in low degree).
The explanations given in the previous paragraphs are completely coincident with the intermediate phenotype between maize and teosinte shown by the F1 and F2 plants of both crossings. This fact is clearly different from what has previously been seen in diploperennial teosinte-maize hybrids (Corcuera and Magoja, 1988).
Last, it can be added that those differences between maize and the teosinte species somehow let interspecific hybrids between them express a wide range of variation. This variation is generally high and useful for maize breeding projects. In addition the high variability shown by plant traits in F1 as well as in F2 progenies is another sign of all possibilities offered by wild relatives to increase the narrow genetic base of maize crops.
Table 1. Means, standard deviation and ranges for plant traits in the OU maize inbred line (P1), Balsas teosinte (P2) and F1 and F2 populations.
Table 2. Differences between means for plant traits of OU maize inbred line (P1), Balsas teosinte (P2), F1 and F2 populations and mid-parent value (MP).
Table 3. Means, standard deviation and ranges for plant traits in the OU maize inbred line (P1), Guatemala teosinte (P3) and F1 and F2 populations.
4. Differences between means for plant traits of OU maize inbred
lines (P1), Guatemala teosinte (P3), F1 and F2 populations and mid-parent
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