Sorghum, Minor crop of Pakistan, Introduction to Sorghum, Selfing and crossing.

Sorghum introduction, selfing and crossing.

1. sorghum Muqadas Bibi 2022-ag-9013 Bushra nazim 2022-ag-9064

2. Sorghum plant biology Technical name: sorghum bicolor Family : poaceae Chromosome number : 2n=2x=20

3. Sorghum plant biology Flower have panicle inflorescence Panicle : Compound raceme Width about 2 to 20cm Length is 4 to 25cm Peduncle: erect or recurved

4. Sorghum plant biology STEM : Nodes and internodes Length is 0.5 to 4.0cm Diameter is about 0.5 to 5cm LEAF : Alternate arrangement in two rows Number : 7 to 30 length : 30 to 135cm

5. Sorghum inflorescence The inflorescence of a sorghum plant is a determinate panicle which is usually compact. shape and colour of the panicle varies from cultivar to cultivar. The primary axis of the panicle is angular and the secondary axes are arranged in whorls around it. The peduncle is usually straight. The length of the panicle varies from 75 to 500 millimetres and the width from 40 to 200 millimetres . panicle contains between 800 and 3000 seeds, which are usually partly covered by the glumes. The glumes are black, red, brown or tan in colour . The spikelets are attached to the raceme branchlets and are borne in pairs, except at the end of the branchlets where groups of 3 usually occur. When the spikelets are borne in pairs, one member is sessile and the other is pedicilate .

6. The spikelets are attached to the raceme branchlets and are borne in pairs, except al the end of the branchlets where groups of 3 usually occur. When the spikelets are borne in pairs, one member is sessile and the othe is pedicilate.Where groups of 3 occur, 1 is sessile and 2 are pedicilate . The sessile spikelet iscomplete and fruitful, while the pedicilate spikelets are sterile or only contain make florets. Sorghum flowers open at night or in the early morning. Those at the tip of the panicle open first and it takes 6 to 9 days before the entire panicle has flowered. Owing to the composition of its flower, sorghum tends to self-pollinate. However, some cross-pollination (about 6%) does occur.

7. Selfing and crossing in sorghum Selfing Bagging : bag the panical for selling to avoid natural crossing by insects. Crossing Artificial cross-pollinations are made by emasculating the seed parent and hand-pollinating it with pollen collected from the pollen parent. Hand emasculations are made by using thin-pointed tweezers, a dissecting needle, a sharp pencil point, or a similar instrument, to remove the anthers. Usually, only a small branch of the panicle is emasculated; the remainder of the panicle is clipped away to permit bagging the emasculated head. Too much trimming may have an adverse effect on seed-set due to drying out of the stigmas Pollen is collected in bags in the same manner as with hybrid com and dusted over the exposed stigmas, or a pollen-producing head may be brushed over an emasculated head.