تأثٌر شكل البورون ومراحل الرش فً نمو وحاصل الذرة (Zea mays L.)

Effect of Boron For and Spray Stages on growth and yield of Corn (Zea mays L.)

This study investigated the effect of mineral and nanoparticules boron and spraying time on growth and yield of Maize cultivar 5018. An experiment was a split plot in randomized complete block design with three replications in spring season 2018 at the field of Ibn Al – Bitar Vocational Preparatory ,Iraq , Karbala. Treatments were foliar application of Boron : (T0 control, T1 mineral boron 1ml.L-1,T2 mineral boron 2 ml.L-1 ,T3 nanoparticles boron 1ml.L-1,T4 nanoparticles boron 2ml.L-1)  and spraying time (45 days and 60 days after planting ).Results showed that the Maize growth and yield were significantly influenced by Boron spraying , where mineral boron 1ml.L-1 gave highest plant height ,number of row per cub, Number of grains per row, Number of grains per cob,cob weight,cob length, grain yield, nitrogen percentage of grains, nitrogen percentage of leaves and protein percentage of grains which was recorded  (163.7 cm,17.62,36.15grain per row,639 grain per cob,294.6 gm,18.27 cm, 10.80 tone per ha,2.09%,2.56 %,13.06 % ) respectively .The maximum of chlorophyll content ,leaves number, 500 grain weight ,potassium percentage and phosphorus percentage of leaves were noticed with nanoparticles Boron 1ml.L-1 which was recorded ( 44.07 SPAD,13.97,178.1 gm,3.09 % and 0.41), respectively compared to control. Foliar application at 60 days after planting was statistically significant of all parameters compared to 45 days after planting. The interaction effect of boron spraying with spraying time. it clearlyindicated that there was significant interaction effect. mineral boron 2ml.L-1 combination with spraying time at 60 days after planting gave highest nitrogen percentage of grain ( 2.19 % ) and protein percentage of grains (13.71 % ).  The interaction between mineral boron 1ml.L-1 and spraying time at 60 days after planting gave highest of plant height ,number of row per cub,  Number of grains per row, Number of grains per cob,cob weight ,grain yield and nitrogen percentage of leaves which was recorded ( 169.2 cm,  18.82,36.23,674,317.8,105.6,11.31 and 2.74 % ) respectively. The maximum of chlorophyll content,leaves number, potassium percentage of lea ves and phosphorus percentage of leaves were found in nanoparticles boron 1ml.L-1 with spraying time at 60 days after planting which was recorded ( 44.35 SPAD,14.33,3.18% and 0.42 %) respectively.The interaction between nanoparticles boron 2 ml.L-1 with spraying time at 60 days after planting gave highest potassum percentage,phosphorus percentage and Boron percentage of grains which was recorded ( 2.99 %,0.38% and 48.62 %) respectively.The maximum of cob length was obtained in mineral boron 1ml.L-1 with spraying time at 45 days after planting which was recorded (19.03 cm)