| || || Fonoti, Pelenato|
| || || Breeding for resistance to taro leaf blight (Phytophthora colocasiae) in Samoa|
Institution: University of the South Pacific.
Subject: Taro leaf blight -- Samoa, Phytophthora diseases -- Samoa, Taro -- Diseases and pests -- Control -- Samoa
Call No.: pac SB 608 .T26 F66 2005
Copyright:Under 10% of this thesis may be copied without the authors written permission
Abstract: The arrival of Taro Leaf Blight (Phytophthora colocasiae) disease in Samoa in the middle of 1993 prompted Samoa to investigate control measures to revive the taro industry. Out of various control strategies, breeding for resistance and evaluation of introduced cultivars were amongst the long term strategies considered. In this work the main objective was to develop and identify acceptable cultivars through breeding of local lines with other introduced lines as well as screening & evaluation of Introduce Palau Lines. In the breeding work, crossing blocks were established at Nu’u Research Station of the Ministry of Agriculture, Forests, Fisheries and Meteorology and the University of the South Pacific, School of Agriculture, Alafua Campus. In 1996 nine (9) successful crosses out of several crosses performed from TLB resistant lines available locally and exotic introduced varieties from elsewhere. The crosses are : PSB-G2 x Niue, Pwetepwet x Alafua Sunrise, PSB–G2 x Alafua Sunrise, Pwetepwet x PSB–G2, PSB–G2 x Toantal, PSB–G2 x Putemu, PSB–G2 x Tusitusi, PSB–G2 x Pwetepwet and Buntaforetwe x Pwetepwet. This was followed by progeny testing, screening, evaluation & selection based on TLB resistant, yield and most importantly taste. Results from this work was the development and identification of 10 best lines for their resistance, plant vigor and good eating qualities. These lines were : Nu’u 1, Nu’u 2 (Talo Seve), Nu’u 5, Nu’u 14, Nu’u 15 (Talo Suga), Nu’u 16, Nu’u 19, Nu’u 21, Nu’u 20 and Nu’u 28 (Talo Semi). Six of these improved lines have been distributed for production and the other four lines will be released later. The screening of Introduced Palau Lines was also done at different locations using Randomized Complete Block designs (RCB). Resistance to TLB, Yield and eating quality were evaluated. Out of eight Palau lines being screened, five were advanced to on-farm trials. The five on-farm trials were conducted at different sites of different agro-ecological conditions. The blocks were arranged in RCB designs. Each block consisted of 40 suckers of each of the five Palau lines and 55 suckers of PSB-G2 planted and guards. Evaluations were again done on TLB resistance, Yield and Taste. Palau 10, Palau 2 and Palau 16 were identified as the best Palau lines and thus recommend for use by farmers. Other Palau lines were potentially good for use as they resist well against TLB. The major impact of this study to the revival of the taro industry of Samoa is the breeding and development of new improved lines of taro. Six of which are now widely grown by farmers of Samoa. In addition, since this was the first screening and evaluation of the Palau Varieties in Samoa, the identification of several Palau lines which are now widely grown by local farmers confirms the pedigree evaluations done elsewhere on these same Palau lines. It is fair to say that this piece of study not only provide promising results for the revival effort of the taro industry of Samoa since the TLB invasion but theoretically confirms that conventional breeding approach do have great impact towards resistance to TLB.