## 3 Discussion
The _Wx\({}^{b}\)_ allele corresponds to AC levels between 15% and 18%. Additionally, alleles such as _Wx\({}^{amw}\)_, _Wx\({}^{la}\)_, _Wx\({}^{smp}\)_, _Wx\({}^{app}\)_, and _Wx\({}^{lp}\)_ demonstrate AC levels between 10% and 15%. Among all variants, the _wx_ allele exhibits the lowest AC level, approximately 2% [55]. We have identified five QTLs (_qGC1.1_, _qGCC3.1_, _qGCC3.1_, _qGC9.1_, and _qGC12.1_) for GC. Among the five QTLs, _qGC1.1_ and _qGC3.1_ have a negative additive effect, indicating that the contributing allele(s) came from BPT 5204. For the other QTLs, the contributing allele came from JAK 686, the high-GPC parent. Multiple QTLs for GC have been reported across the rice genome using different mapping populations [56; 57; 58]. Researchers have identifiedthe \(Wx\) locus on chromosome 6 as the primary determinant of GC, explaining 38.9% of the variation. Further, QTL studies for AC and GC have revealed that the \(Wx\) and \(Alk\) loci, located on short arm of chromosome 6, control these traits along with gelatinization temperature [47]. Two QTLs for KL, \(qkl1.1\) and \(qkl5.1\), were identified on chromosomes 1 and 5. Similarly, [PERSON] et al. (2012) [59] identified a KL QTL on chromosome 1 linked to the marker RM 431. [PERSON] et al. (2004) [60] identified five QTLs on chromosomes 2, 3, 5, 7, and 8, with each explaining more than 10% of the PVE. For KB, one QTL, \(qkb8.1\), was identified on chromosome 8. [PERSON] et al. (2004) [60] detected a QTL, \(qGW8\), controlling KB on chromosome 8. Fine mapping of this QTL identified _OsSPL16_, squamous promoter-binding protein-like 16, and a member of the SBP domain-containing transcription factors [61]. _OsSPL16_ encodes a protein that acts as a positive regulator of cell proliferation. A higher level of expression of _OsSPL16_ promotes cell division and has a positive impact on grain width. On the contrary, a loss-of-function mutation of _OsSPL16_ in basmati improves grain quality by producing more slender grains. [PERSON] et al. (2007) [62] successfully cloned the QTL \(GW2\) (Grain Width on Chromosome 2), which encodes a RING-type E3 ubiquitin ligase that regulates rice grain width. \(GW2\) functions as a negative regulator of cell division by directing its substrate for proteasomal degradation. The loss of function in \(gw2\) leads to an increase in cell numbers within the spikeet hull, thereby contributing to greater grain width, weight, and yield. The major QTL, \(qSW5\)/\(GW5\) (Seed Width/Grain Width on Chromosome 5), plays a crucial role in determining grain width and has been mapped to a 21-22 kb genomic region [63; 64]. \(GW5\) functions within the brassinosterol signaling pathway, modulating grain development by inhibiting the kinase activity of \(GSK2\) on \(OsBZR1\) and \(DLT\), thereby regulating grain width [65]. \(qlb1.1\), a QTL for kernel length-to-breadth (L:B), was identified on chromosome 1. \(qlb\)\(1.1\) exhibited positive additive effects, indicating that the contributing allele came from JAK-686. [PERSON] et al. (2004) [60] identified QTLs controlling grain shape (based on L:B) on chromosomes 2, 3, 5, 7, and 8, while [PERSON] et al. (2021) [66] identified \(qGS7\). \(qGS7\) contained the gene \(GL7\)/\(GW7\), characterized by [PERSON] et al. (2015) [67]. The upregulation of \(GW7\) expression increased the production of slender grains, thereby enhancing the grain's appearance and quality. [PERSON] et al. (2018) [68] identified a QTL, \(GS9\) (Grain Shape Gene on Chromosome 9), that negatively influences the length-to-width ratio of rice grains. \(GS9\) regulates grain morphology by modulating horizontal cell division and vertical cell elongation, thereby affecting overall grain shape. \(qlb1.1\), identified in this study, appears to be a novel QTL, as no loci for L:B have been reported earlier on chromosome 1. [PERSON] et al. (2022) [2] have identified a significant QTL for PTPP on Chromosome 5, while the present work identified QTLs for PTPP on chromosome 9 and 12.