“ORANGE RUST SEVERITY ON RB951541 AND NEW SUGARCANE CULTIVARS RELEASED BY PMGCA/RIDESA/ECSC/UFAL”
Puccinia kuehnii; genetic enhancement; TCH; TRS
In 2009, information about the disease of the sugarcane, orange rust (Puccinia
alaranjada), was released in Brazil. In 2010, the Sugarcane Genetic Improvement
Program, from the Campus of Engineering and Agricultural Sciences, of the
Federal University of Alagoas – PMGCA/RIDESA/CECA/UFAL, released the
cultivar of sugarcane RB951541, with characteristics of high agricultural
productivity, high sugar content and precocity. And, in 2011, the presence of this
disease was confirmed in Alagoas. The RB951541, from 2010 to 2015, had a
great expansion of cultivation in Alagoas and, in this period, it was among the
most planted. However, it began to present problems of susceptibility to orange
rust, with productivity drops and for this reason it was gradually eliminated from
the plantations. Then, in 2021, the PMGCA/RIDESA/CECA/UFAL programmed
the release of five sugarcane sugar cultivars (RB01494, RB011549, RB0442,
RB07818 and RB08791). So, in order to evaluating the behavior of this cultivar in
relation to the orange rust, tests were carried out in the three Research Bases of
the program, and compare them with the susceptible cultivar RB951541.The
plantiig was done between July and August 2018 and the harvests in 2019 (cut
1) and 2020 (cut 2). The variable designed for evaluation were orange rust
severity grades and the agro-industrial characteristics TCH (ton of cane per
hectare), TRS (total recoverable sugar per ton of cane) and TATRH (total TRS
per hectare). In the cultivar RB951541, the average grade to severity of the
orange rust was 6.76 and it was classified as susceptible to the disease; The
cultivars RB01494, RB011549, RB0442, RB07818 and RB08791, had an
average score of 1.00 and were classified as resistant.The cultivars resistant to
orange rust produce 24.51 t ha-1 more than the susceptible cultivar RB951541,
or equivalent to an yield gain of 22.59%. For each unit increment in the orange
rust note, there is a loss of 4.25 t ha-1 and there is no effect of the orange rust on
the TRS variable. The cultivars resistant to orange rust produce, on average, 3.03
t ha-1 of TRS more than RB95154, equivalent to a gain in sugar yield of 20.53%;
The reduction in sugar yield from the first to the second cut of susceptible cultivar,
RB951541, is 22.58%, while the average in resistant cultivars, released by
PMGCA/RIDESA/CECA/UFAL in 2021, is only 7.67%.