اثر تراكم بوته بر عملكرد و اجزاي عملكرد ذرت شيرين و ذرت‌بچه هيبريد KSC 403

Effects of Plant Density on Sweet and Baby Corn (Hybrid KSC 403) Yield and Yield Components

به منظور بررسی اثر تراكم بوته و روش برداشت بر عملكرد ذرت شیرین و ذرت‌بچه آزمایشی طی سال زراعی 92-1391 در دانشگاه كشاورزی و منابع طبیعی رامین خوزستان اجرا گردید. در این آزمایش تراكم بوته در چهار سطح (7، 9، 11 و 13 بوته در متر مربع) و روش برداشت در دو سطح (برداشت به‌صورت 100% ذرت‌بچه و برداشت به‌صورت 100% ذرت شیرین) در قالب طرح بلوك‌های كامل تصادفی با چهار تكرار بررسی شد. تراكم بوته در روش برداشت ذرت‌بچه بر تمام اجزای عملكرد به‌جز وزن بلال بدون پوشش اثر معنی‌داری داشت به‌ گونه‌ای كه با افزایش تراكم بوته، تعداد بلال در واحد سطح و درصد بلال غیر استاندارد افزایش یافت ولی از وزن بلال و درصد بلال استاندارد كاسته شد. بالاترین عملكرد بلال بدون پوشش، بدون پوشش استاندارد و غیر استاندارد به‌ترتیب با 5/2649، 97/766 و 9/3043 كیلوگرم در هكتار در تراكم 13 بوته در متر مربع به‌دست آمد. در ذرت شیرین نیز تراكم بوته بر كلیه اجزای عملكرد معنی‌دار بود و با افزایش تراكم از 7 به 13 بوته در متر مربع، تعداد ردیف در بلال، تعداد دانه در ردیف و وزن هزار دانه كاهش یافت. بالاترین عملكرد دانه (50/1232 كیلوگرم در هكتار) و عملكرد بلال سبز (2/12607 كیلوگرم در هكتار) در تراكم 9 بوته در متر مربع حاصل شد. محاسبه همبستگی بین عملكرد و اجزای آن در ذرت‌بچه بر خلاف ذرت شیرین نشان داد كه بین تعداد بوته در واحد سطح و عملكرد همبستگی مثبت و معنی‌داری وجود دارد.

<strong >Introduction </strong > Sweet corn is the one of the most important types of corn. There is a high amount of sugar in the endosperm of sweet corn than dent corn. Baby corn is the ear of corn that is being harvested in the silking stage before the end of pollination. This crop has an interesting using methods as salad, conserve production and vegetative consumption. Both two sweet and baby corn is obtained from one plant in different growth stages and could be harvested from one corn hybrid. Best yield and quality of baby corn is obtained from sweet corn hybrids, because of high amounts of sugar in the grains and ears. Sweet corn and baby corn could be harvested at early dough stage (with about 30 % of humidity) and early silking stage before the pollination is completed, respectively. Plant density is the most important factor in growing corn, especially in sweet and baby corn. Khuzestan province is one of the main regions of corn production in Iran. In Khuzestan, forage and silage corn have the most production among the summer crops. Corn is planted in two planting date in Khuzestan: early spring and early summer. Spring corn planting produces little grain yield due to Simultaneity of silking stage with hot early summer days. Because of little production and little research about sweet and baby corn, this study was performed and designed. <strong >Materials and Methods </strong > In order to investigate the effects of plant density and harvesting method on sweet corn and baby corn yield, an experiment was performed during 2012-13, in research farm of Ramin Agriculture and Natural Resources University of Khuzestan, located in southwest of Iran. In this experiment, four plant densities (7, 9, 11 and 13 plants.m-2) and two harvesting methods (baby corn and sweet corn) were investigated in an RCB statistical design with four replications. The KSC 403 hybrid was used and investigated in the experiment, as a sweet corn hybrid. Statistical analysis was performed using SAS 9.1 through GlM procedure. Means of all treatments were comprised using least significant difference (LSD) at 5 % probability level. <strong >Results and Discussion </strong > The effects of plant density on yield components of baby corn was significant. Increasing the plant densities increased the ear number and percentage of non-standard ears. The Highest yield of ear without husk, standard and non-standard were obtained (2649.5, 766.97, and 3043.9 kg.ha-1, respectively) with 13 plants.m-2. In sweet corn, increasing plant density from 7 to 13 plants.m-2, decreased row per ear, grain per row and thousand grain weight. Highest grain yield (1232.5 kg ha-1) and green ear (12607.2 kg ha-1) of sweet corn were obtained with plant density of 9.m-2. <strong >Conclusions </strong > Analysis of correlation showed that in both baby and sweet corn, there were positive and significant correlations between yield and its components. There was the high number of non-standard ears in all experimental treatments. In sweet corn, the standard ear without husk yield has positive and significant correlation with all traits except the percentage of standard ear and sheathed ear weight. In addition, unsuitable climate conditions during silking stage reduced the yield of sweet corn through the high number of aborted florets. Yield of sweet corn yield showed negative and significant correlation with grain row per ear and grain per row. However, increasing the ear number.m-2 increased yield in higher plant densities up to 9 plant.m-2 density. Generally, the baby corn had high yield with good quality in this region, but, standard ear percent of the baby corn of the hybrid KSC 403 was very low. On the other hand, sweet corn grain yield was low due to high air temperatures during pollination and maturity stages.