MaydicaOriginal paper Open Access Agronomic Performance and Grain Yield of Mexican Purple Corn Populations from Ixtenco, Tlaxcala Carmen Gabriela Mendoza-Mendoza1, Ma. del Carmen Mendoza-Castillo1*, Fernando Castillo-González1, 2 3 1 Francisco Javier Sánchez-Ramírez , Adriana Delgado-Alvarado and José Agapito Pecina-Martínez 1 Postgrado en Recursos Genéticos y Productividad-Genética, Campus Montecillo, Colegio de Postgraduados. Km 36.5 Carretera México- Texcoco. 56230, Montecillo, Texcoco, Edo. de México. 2 Departamento de Fitomejoramiento, Universidad Autónoma Agraria Antonio Narro. Calzada Antonio Narro 1923, Buenavista, Saltillo, 25315. Coahuila, México. 3 Colegio de Postgraduados, Campus Puebla, Boulevard Forjadores de Puebla No. 205, Santiago Momoxpan, Municipio San Pedro Cholula, Estado de Puebla. 72760. Puebla, México. * Corresponding author: Ma. del Carmen Mendoza Castillo. Postgrado en Recursos Genéticos y Productividad-Genética, Campus Montecillo, Colegio de Postgradua dos. Km 36.5 Carretera México-Texcoco. 56230, Montecillo, Texcoco, Edo. de México. E-mail: [email protected] KeyWords Zea mays L., purple corn, landraces, grain yield, agronomic performance, and San Juan Ixtenco, Tlaxcala Abstract Corn is a crop with an enormous potential for the extraction of anthocyanins which, given their bioactive proper- ties and their ability to act as a natural dye, nowadays are a secondary metabolite of wide interest. In Mexico, several variants of corn that accumulate this flavonoid have been found among corn landraces of blue, red, pink, purple or black kernels. Its grain yield potential and agronomic traits have not been widely documented. Since San Juan Ixtenco, Tlaxcala, preserves the "maíces morados" variant (purple corn) and other variants of colored kernels, in this research the grain yield and agronomic performance of 53 corn populations (landraces and some of them at an early stage of breeding) were evaluated at three locations in order to assess quantitatively those traits. Most populations were of pigmented kernels and yielded between 4494 to 882 kg ha-1, they had a late-male flowering period (105 to 90 days to anthesis) and were of intermediate height (plant height from 254 to 176 cm). When purple corn landraces from Ixtenco were produced under environmental conditions different from those of their place of origin, they suffered maladaptation, complications for the establishment and incidence of ear rot, which reduced their grain yield potential. Despite this situation, 10 purple corn landraces from Ixtenco identified as 38, 8, 34, 39, 13, 3, 4, 1, 9 and 18 were outstanding by their grain yield, agronomic traits and their remarkable capacity to accumulate anthocyanins into the kernel and/or the corncob. Introduction of the diet of the indigenous cultures of Mexico and which, due to its bioactive properties, currently is of In Mexico, the genetic diversity of corn is represented interest to the scientific community (Ryu et al., 2013). and have been kept in 59 to 62 races of corn (Kato This trend has encouraged some plant breeders, et al., 2009). Within this diversity, it has recently been in addition to increase grain yield, to focus on the reassessed that corn landraces possess important genetic improvement and development of varieties nutritional and nutraceutical properties; at the same with differentiated nutritional chemical composition time it has been recognized that its quality is the result and high concentration of nutraceutical compounds of the selection made by Mexican farmers, who have (Serna et al., 2013). An effort has been done to increase chosen attributes such as color, flavor, aroma and carotenoids concentration in the kernels of yellow and texture (Figueroa et al., 2013). red corn, and the amount of anthocyanins in the blue, Since corn landraces have nutritional quality and red, purple or black corn variants. potential to be used as raw material to obtain usable In spite that blue and red corn have been the kernel phytochemicals into the food, pharmaceutical, colors most explored among pigmented corn (Li et cosmetology and textile industries, it is considered that al., 2017), the "maíces morados" of San Juan Ixtenco, these types of corn have a high added value (Gaytán- Tlaxcala, Mexico, are still a revelation, since there’s no Martínez et al., 2013). An outstanding landrace is scientific precedent about their yield and agronomic the pigmented corn, which historically has been part traits and also because they have an intense and dark 64 ~ M 21 Maydica electronic publication - 2019 Purple corn yield and agronomic performance 2 color as the one that Peruvian purple corn exhibits Experimental design and crop management (internationally, it is the most recognized variant of this Populations were established under randomized type of corn). Likewise, they have a similar capacity and complete block experimental design with four even a superior potential to synthesize and accumulate replications. The experimental plot size consisted of anthocyanins in the kernel than the purple Andean two rows, each 5 m long while the spacing between corn (Mendoza-Mendoza et al., 2017), reason why rows was 0.8 m. The population density was of 50 000 they represent a promising source of anthocyanins that plants ha-1. At CP, during the production cycle the crop can be used as a natural dye. However, it is required was kept without humidity restrictions and was fertilized to explore and to characterize this Mexican genetic with the dose 120-80-00. In contrast, at the locations resource in detail. of Tlaxcala (Cañada and Pueblo) the populations were Considering that pigmented corn has a demand in the settled in rainfall conditions and no fertilization was market and there are positive projections about its use applied. at national and international scopes, it was proposed to study the agronomic performance and grain yield of Agronomic performance and grain yield 53 corn populations (landraces and some of them at an To assess the agronomic performance of the early stage of breeding). Most of the germplasm was populations under study, as well as their grain yield from San Juan Ixtenco, Tlaxcala and was established and yield components, ten traits were registered; they at three locations in the High Valleys of Mexico, in were classified into:a) Phenological: days to anthesis order to explore and value them from these points of (DtoA). Consisted on counting the number of days view. Also, some populations with desirable attributes elapsed from sowing until 50 + 1 % of the plants in the and with great potential to avail and to keep into the plot initiated pollen shed. b) Agronomic: plant height pigmented corn genetic improvement program were (PHt). In each replication, five plants surrounded by identified. neighboring plants (full competence) were measured Materials and Methods from the base of the stem to the ligule of the flag leaf, registered in cm; ear health (EHth). In each plot, the Germplasm EHth of the harvested ears was visually evaluated by Fifty-three corn populations were evaluated at assigning a score. It was assumed that because of the three locations during the spring-summer 2014 cycle: symptoms observed, most of the ear rot was caused by in the Experimental Agricultural Field of Colegio de fungal diseases; mainly by Fusarium spp. and in a lower Postgraduados (CP) at Montecillo, Texcoco, State visual frequency by Aspergillus spp. Scores interval of Mexico, and at two locations of San Juan Ixtenco, were from 1 to 5, depending on the ratio of damage Tlaxcala, Mexico: Cañada and Pueblo. Each population caused by the ear rot. The scoring scale used was the (Pop) was identified by an identification number between scale modified by De Leon and Pandey (1989), where: 1 and 53; 37 of the populations were of purple kernel 1 = 0 to 20 %; 2 = 21 to 40 %; 3 = 41 to 60 %, 4 = 61 color (Pop 1 to 22 and 31 to 45), four of blue kernel to 80 % and 5 = 81 to 100 % of rotten kernels on the (Pop 23 to 25 and 46), seven of white kernel and purple cob (which we considered that could be F. verticilloides corncob of the Cacahuacintle race (Pop 47 to 53), one and/or F. subglutinans according to what Morales- of white kernel (Pop 30), one of red kernel (Pop 26), Rodríguez et al. (2007) described. Also, the number of one of pink kernel (Pop 27), one of yellow kernel (Pop ears corresponding to each level of the scoring scale 28) and one of trigueño kernel (creamy white kernel was recorded. Subsequently, in each experimental color, Pop 29). Most of the populations were native unit, the weighted average of ear health was obtained to Ixtenco (41 populations) and 12 were populations by the equation used by Briones-Reyes et al. (2015): at some level of genetic improvement (Pop 19 to 21, Weighted average= 26, 37, 42 to 46 and 52 to 53), named pre-improved populations. Each plant material was represented by 3 kg of seed, supplied by farmers of the community or [(X1.Y1) + (X2.Y2) + (X3.Y3) + (X4.Y4) + (X5.Y5)] acquired at the corn fair that annually takes place in T the town of Ixtenco. Pre-improved populations were provided by the pigmented corn genetic improvement where: Xi = Number of ears in each category of the program. scoring scale; Yi = value of the scoring scale; T = (X1 + X2 + X3 + X4 + X5) = total number of ears in each experimental unit. c) Yield and yield components: 64 ~ M 21 Maydica electronic publication - 2019 Purple corn yield and agronomic performance 3 Grain yield (GrYd). Grain yield per plot was calculated by the formula: ([(EWt