. Conclusions
Phenotyping of germplasm materials is an important undertaking in genetic resource conservation
to ensure efficient conservation management as well as its effective utilization especially in breeding
programs. In this study, 307 rice varieties were characterized to assess their phenotypic diversity.
Diversity analyses showed that 46% of the qualitative traits scored had low diversity indices compared
to only 5% in quantitative traits. Overall, the rice germplasm showed moderate diversity based on
quantitative characters (average index of 0.73). In contrast, the qualitative characters had a low
diversity (average index of 0.45). In comparison to other landraces collections, the diversity in
qualitative traits of our germplasm was higher than what Bajracharya et al., observed in the landraces
from Nepal [18]. The complete qualitative data set of our collection is available in appendix Table A1.
In order to enrich the diversity of qualitative traits in our collection at the PhilRice genebank
exploration trips may be conducted. Collection gaps should be identified in the genebank’s germplasm
collection and should be prioritized in future collection trips. An emphasis on farmers’ varieties that
have been planted in a community for several generations should be considered when planning for
collection trips. It should also considered to look for diversity in qualitative characters that have shown
low diversity indices such as presence of awns, panicle type, and culm habit type among other
characters. Other factors that can be considered during collection of these rice germplasms are the
characters that have high correlations with other characters. Collecting diversity for certain traits or
characters could also lead to a high diversity if the characters are highly correlated.
The success of any conservation program could also be measured by the amount of which these
genetic resources are being utilized. Data generated from characterization of these 307 rice varieties
can be utilized as baseline information for the utilization of these germplasms for any rice breeding Agronomy 2014, 4 231
program such as breeding for ideoypes. For example, 37 accessions meets the plant height criterion
(90–100 cm) for NPT among which 11 accessions also meets the maturity requirement
(110–120 days). Short stature variety was one of the criteria to select a variety for use in a breeding
program to address lodging. The optimal growth duration to achieve maximum yield is about
120 days [8]. A linear increase in total biomass had been observed when the growth duration was
increased from 95 days to 135 days [47]. Efforts should be invested in promoting various stakeholders
in rice production to utilize these germplasms. Effective utilization of these germplasms can be
enhanced if these materials are fully characterized and evaluated for their potential use in breeding
programs. Evaluation of these germplasms should be conducted to assess their potential as donor
parents for the breeding of new varieties with improved responses to various abiotic and biotic
stresses. Broadening of the genetic base through utilization of diverse germplasms in breeding for new
rice varieties may be able to break the yield barrier that rice breeders are currently trying to address.