Efecto de las dosis de nitrógeno y del número de riegos de auxilio en el rendimiento, calidad de fibra y calidad de la semilla del algodón (Gossypíum hirsutum L.)

"La Calidad de la Semilla El manejo de la semilla se basa en normas internacionales y nacionales según sea el uso de la semilla producida. El concepto de calidad total se basa en cuatro conceptos fundamentales: Genético, garantiza la pureza genética, adaptación y potencial de la variedad mejorada o híbrido. Aspecto Físico, garantiza la presencia de semillas completas y fisiológicamente maduras, es decir evita tener semillas quebradas, deshidratadas o mal manejadas. Fisiológico y Sanitario garantiza un alto vigor y germinación en el lote producido. garantiza semilla sana, no sea portadora de virus y hongos, o algún otro tipo de patógenos (Esparza, 1992). En la década de los 80's se consideraba a la germinación, la pureza genética y a la sanidad como criterios únicos para determinar la calidad de la semilla en el laboratorio. Actualmente se incorpora como un cuarto factor el vigor de la semilla, que representa la característica más importante para determinar el comportamiento en campo. El vigor, es "la suma de todas aquellas propiedades de la semilla"

"In Mexico, there is not specific research results to get high quality planting seed. So the objective of this research was to know the best nitrogen dosage and the best number of irrigation to produce high fiber yields and, at the same time, to know the effects of such production factors on the seed quality. This work was carried out at the "Laguna" Experimental Station of Matamoros, Coah. The CIAN Precoz genotype was evaluated at six N dosages (0, 40, 80, 120, 160, and 200 kg/ha) and three irrigation levels (two, three ad four postplanting irrigation). A split plot arrangement in a complet block experimental design with four replications was used. The agronomic variables evaluated were: seed cotton, lint cotton and seed yields, precocity, yield components, and fiber quality. The seed quality was measured through the standard seed germination velocity and seed germination percentage. The accelerated aging test was used to evaluate the seed quality, as the seed germination percentage, and seed vigor through the radicle length and plant dry weight. Results showed significant statistical differences among irrigation number for seed cotton yield, lint cotton yield, seed yields, lint percentage, precocity, fiber strength, and germination velocity. There were also significant effects of N dosage on seed cotton yield, seed yield, lint percentage, and fiber length and strength. The seed cotton yield, lint cotton yield and seed yield increased as increased the number of irrigation (volume of water applied). The best cotton yields were obtained with the 80 kg of N/ha dosage. The open bolis began eight days earlier at the water stressed treatment (two irrigation) than at the other two watering treatments. The best fiber strength was got with three irrigations, and the shorter fiber length was got with the O N dosage. The standard germination test showed that the seed harvested from the two irrigation treatment germinated faster than the seed óbtained of the other two irrigation treatments. But there were not seed germination percentage differences at the end of the test, 12 days after the beginning of the test. The accelerated aging test showed no seed germination percentage and seed vigor differences among irrigation number and N dosage treatments. The standard germination test and the seed germination test after the accelerated aging treatment showed almost the same germination percentages values, so any of them can be used to evaluate the seed quality"