The present investigation was carried out at Sabbahia experimental station for sugar crops. The present investigation aims at inducing polyploidy in sugarcane (Sacharum officinarum) and to investigate its agronomic traits. Colchicine was used to produce polyploidy from three cultivars. These cultivars are: CP 36-13, CO 997 and POJ 287. Buds were treated with 0.05 % solution of colchicine. Treated segments were allowed to germinate until a shoot system length about 40 cm had reached. Plants were then transferred and allowed to grow in the yield. The growing plants were examined for polyploidy firstly by guard cells of stomata, chloroplasts, DNA content in leaves, and chromosomes from adventitious roots initiated in the laboratory. Physicochemical properties for chromatin and deproteinized DNA were estimated. Total soluble solids (T.S.S); plant height; plant diameters were estimated. The results showed that:- number of plastids in guard cells, vascular bundles shape, epidermal cells volume, physico chemical properties, and total soluble solid were proven that polyploid plants were obtained. The present study was capable in producing polyploidy in cultivar CP 36-13, and gave an average of 0.08 %, cultivar CO 997 gave 0.05 %, while for cultivar POJ 287 the study was not capable to produce polyploidy. Plastid number ranged between 9-16 plastids per each cell. The polyploidy plants had large cells, slow growth and large vascular bundles. Chemical composition analysis showed that, DNA, histones, non-histones from the polyploidy plants were increased while the T.m value for polyploidy plants was decreased at 260 nm whereas it was increased at 280 nm. It seems probable this difference was due to DNA under replication. Repressed fraction of genome was decreased in polyploid plants. So the active fraction of genome was increased in polyploid cultivars. With respect to agronomic characters an attempt was carried out to estimate some agronomic traits. Total soluble solids, plant height and plant diameter were increased in polyploidy cultivar. *The present study was capable to produce polyploid plants from cultivar CP 36-13 and CO 997, it was failed in producing polyploid plants from cultivar POJ 287.
تم الحصول على 3 أصناف تجارية منزرعة بمحطة بحوث المحاصيل السکرية بالصبحية بالإسکندرية وهي CP 36-13 ، CO 997، POJ 287 وتم تقطيعها لقطع صغيرة تحتوى کل قطعة على برعم وتمت تغطية احد الوجهين من کل قطعة بمحلول من الکولشيسين 0،05% ثم نقلت بعد ذلک إلى المعاملة بماء الصنبور ثم سمح لها بالنمو حتى يصل طول المجموع الخضري لحجم مناسب حوالي 40 سم ثم نقلت النباتات إلى الأرض المستديمة. وبالفحص تم قياس بعض الخصائص مثل عدد البلاستيدات وشکل الحزم الوعائية وحجم خلايا البشرة. کذلک تم قياس الخواص الفيزوکيماوية للکروماتين والـ DNA المنزوع من انوية الأوراق مثل کمية الـ DNA، کمية البروتينات الکروموسومية الکلية. کمية الهستونات في الأنوية.کمية البروتينات اللاهستونية. تقدير درجة حرارة إنصهار الکروماتين وکذلک DNA خالى البروتين على طول موجة 260 nm، وطول موجة 280 nm. تقدير منحنيات الانصهار للکروماتين. تقدير الجزء المثبط والجزء النشط من الجينوم کدالة للنشاط النسخي کدلائل مبکرة على النمو والإنتاجية. علاوة على ما تقدم فقد تمکن البحث الحالي من انتاج تضاعف للمجموعة الکروموسومية لنباتات الصنف CP 36-13 ، والصنف CO 997 بينما فشل إنتاج تضاعفات من الصنف POJ 287.