Grain yield

The feasibility of the crop is defined by this character, for higher profits. Average yields (t ha^-1) obtained in the 4 years of trial were very different: 2.95 in 2004; 2.36 in 2005; 2.89 in 2008; 1.45 in 2010 (Table 3). The years in which the grain yield was higher are 2004 and 2008, with 2.95 and 2.89 t ha^-1 in respective manner; the lowest values of both factors occurred in 2005 and 2010.

Table 3 Agronomic characters of 18 outstanding landraces of tiny Zapalote racefor during four years of assessment. San Pedro Comitancillo, Oaxaca. 

Medias con la misma letra en cada columna son estadísticamente iguales (Tukey 0.05); RG= rendimiento de grano; DFM= días a floración masculina; DFF= días a floración femenina; ALP= altura de planta; ALM= altura de inserción de la mazorca; LM= longitud de la mazorca; DM= diámetro de la mazorca; NHM = núm. de hileras de la mazorca; LG= largo del grano; AG= ancho del grano.

The varieties with the highest average yields were COL-36 with 2.97 t ha^-1 and OAX-838 with 2.82 t ha^-1, which belong to the people of Union Hidalgo and Santiago Laollaga respectively; identified with tiny Zapalote race, from the Isthmus of Tehuantepec, Oaxaca, distinguished as the geographic range of this race (Wellhausen et al., 1957; ^{López et al., 2005})

Furthermore, although not considered in the assessment improved materials used as controls, ^{Lopez et al. (2005)} and ^{Taba et al. (2006)}, agreed that in the Isthmus of Tehuantepec, strong winds can cause lodging of stem and root, tiny Zapalote race maize, who is early maturing, provides more reliable yields, through years, that varieties more yield, identified as having late maturity. In this regard, it has been shown that often landraces exceed or equal in yield to improved varieties, and can therefore be used by other producers and breeding programs.

In 2004 and 2008, some overlaps between the higher yielding varieties were introduced, and among the lowest yield, which did not occur in 2005 and 2010. In other words, various materials evaluated with high yield in 2004 and 2008 were those of lower yield in 2005 and 2010. However, Table 4 varieties that had a good level of yield, and showed similar positions in the four years of assessment are observed, as in the case of collections: OAX-838, COL -36, COL-45 and ZAP MOR.

Table 4 Grain yield (t ha^-1) of 18 outstanding landrace maize during four years of testing in San Pedro Comitancillo, Oaxaca (Tukey 0.05). 

It is observed that, the 18 collections studied had high average yield, with respect to reporting INEGI (2002), which is 1.25 t ha^-1 suggesting continuing studies specifically on them to detect other attributes that allow recommending for commercial plantings or be considered in a breeding program. The recommendation refers to the physical characterization of grain and processing tests of “nixtamalización” of tortillas and tortilla chips on physical study, which is the use identifying germplasm of tiny Zapalote race.

The ANOVA reported statistical significance for variables days to male and female flowering; defining characteristics earliness of crops. The importance of this breed is its earliness (^{López et al., 2005}), which allows for at least two crops on the same land per year; hence, for a selection criterion are defined as desirable materials with lower values are located. The period required to reach collections male flowering was 45.5 to 51.5 days after sowing (Table 5) highlighting the COL-34 as the lowest number of days, while the COL-31 was requiring more days blooming. In this regard it is noted that ^{Taba et al. (2006)} report 76 days on average for the days of anthesis. For female flowering period was 47.75 to 53.5 days, highlighting the same materials in blooming.

Table 5 Variables of 18 outstanding agronomic landrace test during four years in San Pedro Comitancillo, Oaxaca (Tukey 0.05). 

DFM= días floración masculina; DFF= días a floración femenina; ALP= altura de planta; ALM= altura de mazorca; LM= largo de mazorca; DM=diámetro de mazorca y NHM= núm. de hileras de mazorca.

In the above conditions, this breed maize responds advantageously due to its low height and its tolerance to lodging. Plant height was 110.38 cm for variety OAX-823, to 150.13 cm where the variety COL-45 (Table 5) was located. For the height of ear position, the OAX-823 range with the lowest value (58.75 cm) was located, while the highest value was for the COL-29 with 79.63 cm. The above values are consistent with those reported by ^{Wellhausen et al. (1951)}, noting that plant height in this breed of maize is 1-2 m, and ^{Taba et al. (2006)}, who found values of 156 cm in plant height and 82 cm for ear height.

The ear length values recorded 9.09 cm (COL-34) to 12.63 cm (COL-62), offering reduced variation in this character, perhaps because the evaluated collections are of little heterogeneity, despite the separation statistical groups in Table 5. The diameter of 3.53 points cob figures cm (OAX-823) to 4.7 cm (ZAP MOR) between genetic materials. The number of grain rows per ear in the studied was characterized germplasm 9.5 (OAX-823) to 15 (ZAP MOR). ^{Wellhausen et al. (1951)} considered that, the race tiny Zapalote can occur in 10-12 rows and ear diameter of 4 to 4.4 cm. With the values found with those reported in these variables, grain yield identifying this breed maize can be considered small.

The length of the cob is comparable to that of the landraces identified as intermediate and late by ^{López et al. (2005)}. ^{Taba et al. (2006)} reported an average ear length 12 cm, diameter 4.4 cm cob and 11 rows of maize in the cob.

Conclusions

In the Isthmus Oaxaca there is a wide genetic variation among and within populations of breed tiny Zapalote race maize. Grain yield for varieties and years of assessment fluctuated between 1.73 to 2.97 t ha^-1. The varieties with higher average yields were 36 and COL-OAX-838. The highest stability in this character was presented to OAX-838, COL-31, COL-32 and COL-51.

Male flowering showed a variation of 45.5 to 51.5 days after planting, while silking the range of 47.75 to 53.5 was days after sowing. Plant height fluctuated from 150.13 to 110.38 cm, while the height position of the ear was 58.75 to 79.63 cm.

The tiny Zapalote race maize, whose production environment is the Isthmian region of Oaxaca; has been and remains the most appropriate, for their adaptation and characteristics of production and consumption.