check out "native seed search " from Tucson AZ.
www.nativeseedsearch.org they have a lot of seeds MOST from the south West U.S.A. AND MEXICO many from desert areas and Indian reservations . Also check out : "Garden seed inventory ": an inventory of seed catalogs listing all non-hybrid vegetable seeds available in the United States and Canada
Whealy, Kent.
Personal Author: Whealy, Kent.
Title: Garden seed inventory : an inventory of seed catalogs listing all non-hybrid vegetable seeds available in the United States and Canada / originally compiled by Kent Whealy ; inventories updated by Joanne Thuente.
Edition: 4th ed.
Publication info: Decorah, Iowa : Seed Saver Publications, c1995.
Physical descrip: 628 p. ; 23 cm.
Subject term: Vegetables--Seeds--United States--Catalogs.
Subject term: Vegetables--Seeds--Canada--Catalogs.
Subject term: Vegetables--Seeds--Catalogs.
Subject term: Seed industry and trade--United States--Directories.
Subject term: Seed industry and trade--Canada--Directories.
ISBN: 1882424530 (softcover)
ISBN: 1882424522 (hardcover)

You may want to try "Hopi pink corn" (70 days) it does best in all drought tests and is sold by native seeds search of Tucson AZ . You might want to try some and breed some in to your strains.
The carobe tree and sunflowers are drought tolerant .

High Country Roses of Vernal, UT, USA has a list of drought tolerant roses at the very bottom of the page weblinked below. I'll be planting some of their Rugosa varieties this fall. I'll have to let you all know how they survive any future droughts.

Here is a link that might be useful: High Country Roses, Specialities

My favorite is High Country Gardens:

http://www.highcountrygardens.com/

please send me lists of seeds suitable for planting during dry season on the philippines. including their technology.