Improved Flowering and Pollen Fertility in Sugarcane under Increased Night Temperatures1
- Nils Berding2
A shortage of male fertile sugarcane clones often restricts cross-pollination at the Meringa Sugar Exp. Stn. Extensive pollen testing revealed substantial variability on a micro-environmental scale, indicating the environment may be sub-optimal for pollen development.
Four clones from each of three flowering groups (early, mid, and late season) were chosen on the basis consistent flowering but variable pollen stainability. Two adjacent replicated field trials were planted. One trial was enclosed at night with a mobile plasticsheathed shed and maintained at 22 to 23 C from 22 March, 2 weeks after photoinduction commenced, until 15 June 1979, 6 days before routine cross-pollination finished. After 22 March, the average external minimum temperature was usually well below 21 C, regarded as critical for good pollen fertility development in sugarcane.
The heated environment produced more profuse flowering (77 vs. 61%, for the whole season; 64 vs. 35%, during cross-pollination), increased panicle availability for crossing (84 vs. 57%), and accelerated flowering by an average of 12 days. This latter effect provides an additional technique for making crosses among clones which do not normally flower at the same time.
Pollen production in both environments was similar but stainability (starch-iodine test) was significantly higher in the heated environment (19 vs. 9%, stained grains). The later the flowering group, the greater was the improvement obtained.
Crosses using male flowers from the heated environment produced significantly more seedlings (614 vs. 325/5 g “seed”, in 16 paired crosses; 572 vs. 225, over 78 crosses).
The heated environment significantly increased flowering, pollen stainability, and germination count and is expected to have an important practical application.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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