by Tan, D.L.S, Roa, J.R, Gundaya, E.A
Published in CIAT publication (CIAT) (1996)

by Amestoso F.J, Roa J.R, Truong Van Den
Year of Publication 1989

by Bacusmo, J.L, Vega, B.A, Evangelio, F.A, Roa, J.R, Lauzon, R.D. (Visayas State Coll. of Agriculture, Baybay, Leyte (Philippines))
Year of Publication 1996

by Palomar, M.K, Roa, J.R. (Visayas State Coll. of Agriculture, Baybay, Leyte (Philippines). Philippine Root Crop Research and Training Center)
Published in PCARRD Book Series (Philippines) (1991)

by Roa, J.R
Year of Publication 1995

by Roa, J.R
Year of Publication 1992

by Roa, J.R., Visayas State Univ., Baybay, Leyte (Philippines). Philippine Rootcrops Research and Training Center
Published in Philippine Journal of Crop Science (Philippines) (01.05.2011)

by S.P. ROA,J.R. BARAN,JR.,JING NAIYONG
Year of Publication 30.11.2005

by Roa, J. R
Published in Sustainable Poverty Reduction in Less-favoured Areas (2007)

by Roa, J.R. (Visayas State Coll. of Agriculture, Baybay, Leyte (Philippines))
Year of Publication 1999

by Roa, J.R, Palomar, L.S, Diamante, L.M. (Visayas State Coll. of Agriculture, Baybay, Leyte (Philippines))
Published in Philippine Journal of Crop Science (Philippines) (01.04.1995)

by Gundaya, E.A, Evangelio, F.A, Sanico, R.T, Roa, J.R, Orias, R.R, Ramirez, M.C.U
Year of Publication 1995

by Channer, G.D.A, Roa, J.R. (54 Lyford Road, London SW18 3JJ (United Kingdom))
Year of Publication 1994

by Palomar, L.S, Roa, J.R, Diamante, L.M, Arcena, C.K. (Visayas State Coll. of Agriculture, Baybay 6521-A, Leyte (Philippines))
Published in Philippine Journal of Crop Science (Philippines) (01.05.1996)

by Roa J.R, Francisco H.A, Del Mundo A.M, Garzon E.D, Mula R.P
Year of Publication 1991

by Palomar, M.K, Sanico, R.T, Vasquez, E.A, del Rosario, C.S, Roa, J.R, Tan, P.M. (Visayas State Coll. of Agriculture, Baybay, Leyte 6521-A (Philippines))
Published in Philippine Journal of Crop Science (Philippines) (01.05.1994)

by Roa, J.R, Data, E.S, Loreto, A.B. (Visayas State Coll. of Agriculture, Baybay, Leyte 6521-A (Philippines). Philippine Rootcrop Research and Training Center)
Published in Philippine Journal of Crop Science (Philippines) (01.05.1994)

by Garzon, E.D, Francisco, H.A, Roa, J.R, Mula, A.P, del Mundo, A.M. (International Potato Center, Los Banos, Laguna (Philippines). User's Perspective with Agricultural Research and Development)
Year of Publication 1991

by Truong, Van Den, Roa, J.R, Amestoso, F.J. (Visayas State Coll.of Agriculture, Baybay, Leyte (Philippines). Philippine Root Crop Research and Training Center)
Year of Publication 1990

by Roa, J.R, Truong, Van Den, Amestoso, F.J. (Visayas State Coll. of Agriculture, Baybay, Leyte (Philippines). Dept. of Agricultural Chemistry and Food Science)
Year of Publication 1990