Abstract:
The study aimed at examining tolerance, antixenosis, and antibiosis expression in seven
sugarcane (Saccharum officinarum) (L.) germplasm for Yellow Sugarcane Aphid (YSA) (Sipha
flava) resistance. A 7×2 factorial design, laid out in a complete randomized block design and
replicated four times was used. Variety was the first factor, with seven treatment levels
(96-1107, 00-1165, ZN 10, ZN 8, ZN 9, ZN 3 L, and N14). Aphid infestation was a second factor,
with two treatments (un-infested (control) and infested). Data was collected on tolerance
parameters (chlorophyll loss, net photosynthesis, transpiration and stomatal conductance),
antibiosis parameters (total protein content, total soluble sugars, nitrogen, phosphorus,
potassium, calcium, and magnesium) and on antixenosis parameters (trichomes and aphid
numbers). GenStat 18th edition was used for statistical analysis and Fisher’s Least Significance
Difference (p<0.05) was used for mean treatment separation. Different sugarcane varieties
varied significantly (p<0.05) on resistance mechanisms to YSA. Three levels of PRI (tolerance,
antibiosis, and antixenosis) was expressed in 00-1165 sugarcane accession, while varieties; ZN
8, ZN 9 and ZN 3 L showed tolerance and antixenosis. Interaction effects (p<0.001) between
treatments were observed on gas exchange, total soluble sugars, chlorophyll loss, phenol
content, and flavonoid content. Variety 00-1165 did not show any differences in chlorophyll
loss between the aphid infested and uninfested treatments. Similarly, variety ZN 3 L did not
show significant variation in flavonoid concentration between the aphid infested and
uninfested treatments. Indeed, the study clearly shows that sugarcane varieties have resistance
mechanisms to YSA.
