**4.2. Potential of local × improved combination to enhance a locally adapted maize population**

Based on the results of the research paper carried out by [25], plants of the local population JAGUEY were crossed with an improved population to determine the value of a breeding material to enhance a local adapted maize population. Introgression of exotic germplasm to adapted material in maize has been a powerful tool to increase genetic variability in the local population, as well as to transfer favorable alleles, such as insect or disease resistance. The proportion of the exotic germplasm has been addressed in several studies to determine the usefulness of the foreign material on the foundation of breeding base populations [26–28]. The relevance of the introgression of foreign or exotic germplasm to an adapted population may change depending on the particular objectives. For instance, the improvement of a local farmer population by the introgression of exotic or foreign germplasm requires the identification of a good source donor and the establishment of the selection strategy. However, the application of breeding techniques to local maize populations may change their genetic structure, being the level of change related to the breeding methodology and the selection pressure. Besides the improvement of the local material, it is essential to preserve as much as possible the genetic variation accounted by the local material. In this case, the maize population JAGUEY adapted to Jagüey de Ferniza, Saltillo, Coah., Mexico, was considered the local material (L), and used to assess the contribution of an improved material introgressed to the local population [25]. This local population is a white dent type of the race Conico Norteño, adapted to rainfall conditions, such as low fertilizer inputs and limited water supply, and it is maintained by farmers through an empirical mass selection. The improved material (I), considered the foreign material, was an early flowering experimental population (CPRE), previously chosen, based on its combining ability performance when crossed with local populations [29]. Initially, full sib (FS) families were obtained throughout plant-to-plant crosses between plants from the local (JAGUEY) and the improved (CPRE) maize populations [29]. Derived families evaluation data included days to flowering (anthesis and silking), plant and ear heights (m), husk cover (%), stalk and root lodging (%), number of ear per plant, and grain yield (t ha−1) adjusted to a 15% moisture content. Best families (10%) were selected based on the evaluation data under irrigated and the rain fall conditions, with special emphasis on the performance under the rainfall environment [30]. After the first genetic recombination of selected families (50:50 of local and improved germplasm), three full sib selection cycles were applied to develop an improved native maize variety named JAGUAN [31]. In addition to grain yield, the selection procedure included number of ears per plant, husk cover, with special attention in keeping the same flowering date as the original native population using selection indices [32]. The difference in grain yield between JAGUAN and the local variety JAGUEY, the original population was 24.5%. JAGUAN is a variety developed for rain-fed conditions, with intermediate biological cycle (83–90 days flowering), plant height of 2.5 m, selected by high planting densities (50,000–60,000 plants ha−1), adapted to the transition to highland areas (above 1800 m), and with phenotypic expression as the original native population [29].

**References**

Fitotecnia Mexicana. 2002;**25**(1):17-23

The Netherlands: IPGRI; 1996. p. 9-18

Transgenic Maize. Mexico: CIMMYT; 1997. p. 56-66

Secretaria de Agricultura y Ganaderia; 1951. p. 237

Moreno: Mexico; 2011. p. 61

1996. p. 22

ed. URSS; 1985. p. 1-22

1st ed. Mexico: SOMEFI; 2010. p. 13-25

p. 4-12

[1] SIAP. Anuario estadístico de la producción agrícola [Internet]. 2016. Available from: http://nube.siap.gob.mx/cierre\_agricola/ [Accessed: July 19, 2017 [Updated: 2016]

Genetic Potential and Usefulness of Native Maize Populations in Developing Novel Germplasm…

http://dx.doi.org/10.5772/intechopen.71360

111

[2] Herrera C BE, Macias L A, Diaz R R, Vazquez R M, Delgado A A. Uso de semilla criolla y caracteristicas de mazorca para la seleccio de semilla de maiz de Mexico. Revista

[3] Aguirre M VJ, Rincon S F, Ramirez S R, Colom A OG, Razo M MG. Modelo para la conservacion de maices criollos en el sureste de Coahuila, Mexico. Vicente Javier Aguirre

[4] Eyzaguirre P, Iwanaga M. Farmer's contribution to maintaining genetic diversity in crops. In: Eyzaguirre O, Iwanaga M, editors. Participatory Plant Breeding. Wageningen,

[5] Louette D. Seed exchange among farmers and gene flow among maize varieties in traditional agricultural systems. In: Serratos JA, Willcox MC, Castillo F, editors. Gene Flow among Maize Landraces, Improved Maize Varieties, and Teosintle: Implications for

[6] Louette D, Smale M. Genetic Diversity and Maize Seed Management in a Traditional Mexican Community: Implications for In Situ Conservation of Maize. CIMMYT: Mexico;

[7] Kato Y TA, Mapes S C, Mera O LM, Serratos H JA, Bye B RA. Origen y Diversificacion del Maiz: Una Revision Analitica. 1st ed. Mexico: Universidad Nacional Autonoma de Mexico, Comision Nacional para el Conocimiento y Uso de la Biodiversidad; 2009. p. 115

[8] Wellhausen EJ, Roberts LM, Hernandez X E, Mangelsdorf PC. Razas de maiz en Mexico. su origen caracteristicas y distribucion. 1st ed. Mexico: Oficina de Estudios Especiales,

[9] Ortega P R. Descripcion de algunas razas mexicanas de maiz poco estudiadas. In: Ortega P R, editor. Variedades y razas mexicanas de maiz y su evaluacion en cruzamientos con lineas de clima templado como material de partida para fitomejoramiento. 1st

[10] Rincon S F, Hernandez P CJ, Zamora C F, Hernandez C JM. Recoleccion de maices nativos de Coahuila 2008. In: Rincon S F, Castillo G F, Ruiz T NA, editors. Diversidad y distribucion de los maices nativos en Coahuila, Mexico. 1st ed. Mexico: SOMEFI; 2010.

[11] Rincon S F, Castillo G F, Ruiz T NA, Illescas P CN, Ramon G L. Diversidad de los maices nativos de Coahuila con base en caracteres de la mazorca. In: Rincon S F, Castillo G F, Ruiz T NA, editors. Diversidad y distribucion de los maices nativos en Coahuila, Mexico.
