The recent investigation was carried out to determine the effect of different gamma-ray doses and 900 W (2450 MHz) microwave radiation with various exposure times, separately or in combinations, on the yield, yield components, and chemical properties of guar (Cyamopsis tetragonoloba), as well as, to detect variation induction. The cDNA-SCoT technique was used to obtain molecular markers related to some traits. SSR technique was used to sequence the target fragment related to plant height. Gamma-ray doses of 150 and 250 Gy alone, and in combination with 900 W microwaves irradiation applied with different duration or time span (1, 2, 3, and 4 min) influenced the plant height significantly, as well as, number of tillers plant-1 and fresh and dry forage yield, and fresh and dry leaf stem-1 ratio. In the second sample, seed yield at harvest time, e.g., pods plant-1, weight of pods plant-1, whole plant dry weight, number of seeds pod-1, length of pod, 100-seed weight, and seeds yield were affected by irradiation with different and varied responses. In the M1 generation, the 18 SCoT primers produced 327 bands ranging between 151–2895 bp in size, out of which 282 were polymorphic (86.24%). In the M2, the 18 SCoT primers produced 328 bands ranging between 212–2661 bp in size, out of which 299 were polymorphic (91.16%). The M1 and M2 generations exhibited 89 positive and 39 negative bands, which could be used as marker assisted-selection in response to treated guar plants with different gamma ray doses, separately or in combinations with microwave treatments.

Guar is an economically significant forage crop and a multi-purpose plant. In Egypt, with a limited gene pool of guar, gamma ray (γ-rays) and microwave pre-treatment, individually or in association, were used to generate genetic variability and develop new high-yielding genotypes. Guar seeds of the variety Shandaweel-9 were irradiated with different γ-ray doses (i.e., 0, 150, 250, and 350 Gray “Gy”), either individually or along with the irradiation with 900 W microwave treatments applied for different exposure times (1, 2, 3, and 4 min), then grown at Agricultural Research Center, Giza, Egypt in 2019, and 2020 summer seasons. The results indicated that gamma-ray doses of 150 and 250 Gy, stand-alone or with microwave treatments, significantly influenced guar plant height and crude protein in M1 and M2. Fragments with 925, 1427, and 2145 bp linked to plant height and crude protein were eluted from the gel, sequenced, and then registered on GenBank. The fragment linked to plant height received accession No. LC681484.1 and fragments linked to crude protein received accession No. of OK617330.1 and OK617331.1. The sequenced fragments underwent translation to protein, then proceeded to proteome analyses. Depending on the sequence analysis, the 925 bp fragment consisted of a 302 bp ORF (open reading frame) encoded with 302 amino acids. However, the fragment of 1427 bp has 433 ORF, and the fragment of 2145 bp has 705 ORF. The LC681484.1 might have a role in plant elongation. On the other hand, OK617330.1 and OK617331.1 might be responsible for cell wall protein organization.