Inheritance of Root-lodging in Sweet Corn ( Zea Mays L.)

Root lodging in sweet corn ( Zea mays L.) is an important cause of yield loss due to difficulty of mechanical harvest. Supersweet corn genotypes which are highly desirable for their good eating quality have been reported as susceptible to lodging (Tracy, 1997). The objectives of this study were to evaluate the mode of inheritance of lodging resistance in a shrunken-2 (sh2) sweet corn population and examine possible relationships among morphological characteristics related to lodging under field conditions. Two inbred lines, R33 (susceptible to lodging) and Mp708 (resistant to lodging), were crossed and the parents and resulting progenies (F1, F2, F3, F4, BC1, BC2, and BC3) were evaluated in the field from 1996 to 1998. Data on root-lodging resistance at different stages, plant height, ear height, and stem diameter were taken during on an individual plant basis. Generation mean analysis indicated that much of the genetic variation for root-lodging resistance was additive. Narrow-sense heritability estimates for lodging-resistance were moderate for 1996 and 1998. At least two genes were influencing root-lodging resistance. Root-lodging resistance in sh2 phenotypes was improved by pedigree selection. Field evaluations for root-lodging at 12 weeks after planting differentiated resistant genotypes better than field evaluations at 8 weeks. El acame de raíces en maíz dulce ( Zea mays L.) es una de las principales causas de pérdidas de rendimiento debido a las dificultades que ocasionan la caída de las plantas al momento de realizar la cosecha mecánica. Los genotipos de maíz superdulces, los cuales son muy demandados por su buena calidad comestible son señalados como muy susceptibles al acame (Tracy, 1997). Los objetivos de este estudio fueron evaluar el modo de herencia de la resistencia al acame en una población de maíz "shrunken-2" (sh2) y examinar la posibles relaciones entre características morfológicas relativas al acame en condiciones de campo. Dos líneas, R33 (susceptible ) y Mp708 (resistente), fueron cruzadas, posteriormente los progenitores y las progenies resultantes (F1, F2, F3, F4, RC1; R2 y RC3) fueron evaluados en condiciones de campo durante el período 1996-1998, se llevaron registros por planta de, resistencia al acame de raíces a 2 edades del cultivo, altura de planta, altura de la mazorca y diámetro del tallo. El análisis de la media generacional indicó que mucha de la variación genética para la resistencia genética al acame de raíces fue aditi