PRODUCTIVITY AND PHYSIOLOGICAL POTENTIALITY OF SOME SILAGE MAIZE GENOTYPES

Abstract

: An experiment was conducted in the summer season of 2019 at the Agricultural Experiment Station, Faculty of Agriculture (El-Shatby), Alexandria University, Egypt. The main objectives of this study were: (i) to trace the physiological development of maize hybrids with reference to growth parameters, and (ii) to assess yield, quality and responses of silage maize genotypes to plant densities. Eight corn hybrids were used in this study, seven were single cross hybrids three of them were white-grain: SC10, SC128, SC131 and four yellow-grain SC166, SC167, SC168, SC176 and one white-grain three-way cross namely TWC321. Hybrids were developed by the Ministry of Agriculture, Maize Research Program, and Agriculture Research Center, Egypt. The fieldwork included two plant densities 20,000 and 35,000 plants faddan -1 i.e .; 47,619 and 83,333 plant hectare -1 , traits were measured at three development stages i.e. (35, 70 and 105 days after emergence). Spilt -plot design in a randomized complete block design, with three replications was employed. Sub-plot was 18 m 2 of six ridges each of 0.75 m width and four-meter long. Corn hybrids were distributed in the main–plots, whereas, the sub-plots contained the two plant densities. The results indicated that, as plant density increased from 47,619 to 83.333 plant hectare -1 , stalk diameter decreased from 24.53 to 20.91 mm, upper leaf chlorophyll content decreased from 46.45 to 42.01 SPAD, lower leaf chlorophyll content decreased from 36.74 to 31.31 SPAD, the no. of ears per plant decreased from 1.38 to 1.10 and plant dry weight decreased from 293 to 195 g plant -1 , respectively. Plant densities significantly gave similar plant dry weight after 35 days from emergence, while, low plant density (47.619 plant ha -1 ) gave the heaviest plant dry weight after 70 and 105 DAE (279 and 584 g plant -1 , respectively).The results indicated that relative growth rate of maize hybrids during the first developmental stage (35-70 DAE) was significantly superior to measured figures in the late season stage (70-105 DAE). Also, hybrids with significantly higher RGR during the early season’s stage were SC10, SC128, SC131 SC168 and SC176. While SC167 and TWC321 significantly exhibited lower values. By the late season stage (70-105 DAE) all hybrids had similar values of RGR. Effect of plant density on total dry forage yield over maize-hybrids and developmental stage, the highest significant total dry forage yield was recorded at a plant density of 83.333 plant hectare -1 (15.70 t. ha -1 ), while, the plant density of 47,619 plant hectare -1 significantly recorded lower value (13.92 t. ha -1 ). Maize hybrids were significantly divided into two groups regarding protein yield. A superior group with values 2.19, 1.96, 1.96, 1.61 and 1.84 t. ha -1 for SC10, SC131, SC168, SC128 and SC176. The second lower group included SC167, TWC321 and SC166 with values of (1.59, 1.45 and 1.20 t. ha -1 respectively).